PDA

View Full Version : Metabones "Speed Booster": results & influence on choice of camera bodies and lenses!


Dr Klaus Schmitt
January 14th, 2013, 08:26 AM
Metabones + Dr Brian Caldwell announced their new "Speed Booster",
actually a well known principle from astronomy, a focal reducer or telecompressor.

See here: Metabones - Metabones and Caldwell Photographic introduce Speed Booster (http://www.metabones.com/info/105-info/154-speed-booster)

White Paper is here: http://www.metabones.com/images/metabones/Speed%20Booster%20White%20Paper.pdf

Test is here: An adaptor which claims to make your lens, faster, wider and better!! This is NOT an April Fool’s! | Philip Bloom (http://philipbloom.net/2013/01/13/speedbooster/)

****

Done that before for my sort of photography, see on my BLOG: Photography of the Invisible World: Search results for reducer (http://photographyoftheinvisibleworld.blogspot.de/search?q=reducer)

without reducer/telecompressor:
http://www.pbase.com/kds315/image/142157424/large.jpg

with reducer/telecompressor:
http://www.pbase.com/kds315/image/142157427/large.jpg

overall system changed from f4 to f1.6 and the focal length from 84mm to 34mm!

Asher Kelman
January 14th, 2013, 12:38 PM
Klaus,

Do we have to use the 24MP NEX version to get the benefits of the increased MTF, or is the MTF improvement referred to inclusive of the sensor?

Asher

Dr Klaus Schmitt
January 14th, 2013, 12:43 PM
No, with any such type of camera (NEX, m4/3) you would benefit from faster speed and wider angle!

Asher Kelman
January 14th, 2013, 12:52 PM
No, with any such type of camera (NEX, m4/3) you would benefit from faster speed and wider angle!

So how much improvement in the MTF of lenses can these current 16 and 24 MP sensors accommodate?

Asher

jake klein
January 15th, 2013, 01:37 PM
Any one know if a version made for DX cameras might be coming out?

I would love this with my 85mm f1.4D on my D90!

Jerome Marot
January 15th, 2013, 10:40 PM
Any one know if a version made for DX cameras might be coming out?

Unlikely. For the optical system to work, the lens needs to be put closer to the film plane.

This kind of system, already known as a focal reducer in astronomy, typically gives poor corner sharpness. The effect should be even more pronounced on short focal lengths.

Doug Kerr
January 16th, 2013, 06:15 PM
The principle here is just that of any inboard focal length converter, in this case with a ratio less than 1.

All the basic math works the same way. The f-number of the "new composite" lens is less (larger relative aperture) than that of the base lens itself (its true f-number, not an "effective f-number", as is often said).

The focal length converters we most often use were originally introduced to "convert" a "normal" lens into a "telephoto" lens (using that term in the sense of a lens with a focal length significantly greater than that of a "normal" lens), and thus were often called "teleconverters". That name stuck, even when we apply them to a lens that is already a "telephoto" lens.

The device discussed here could be called, in that same vein, a "wideconverter".

Best regards,

Doug

Ben Rubinstein
January 19th, 2013, 10:18 AM
I am watching this with a great deal of interest.

I am in a position at present to buy a new camera. My needs are FF, works with my present canon lenses, not huge, a certain level of IQ (very personal of course) and live view with peaking for use with manual focus lenses when handholding the camera.

The choice to date had been a 5D3. The build and IQ are superior to the 5DII which I love to hate, it is a camera whose features would be sufficient for the next 7 or so years for my personal usage (or in other words, shoot it till it dies then buy whatever looks good) and of course it works with all my current equipment. For use with manual 'alt' lenses there is a Magic Lantern hack which provides peaking and I had intended to buy the GGS SWIVI LCD viewfinder to provide stability when focusing using the LCD.

Few issues though. First of all there have been numerous reports that the paint finish on the camera is very thin and a lot of photographers are reporting that their cameras after 6 months look 5 years old. Something they had not had on previous Canon 5 series bodies. I've seen some examples and neither of my battered 5Dc's looked even close to as bad after 7 years of hard use!

Second of all the low light focus on the 5D3 is slow. There are reports that it is slowing down even further in low light when a flash is attached and many wedding shooters are reporting that the camera is unuseable in typical wedding lighting. Canon have been notified in an official thread on the canon forum. I would discount this if I hadn't noticed myself that the focus with a 50mm 1.4 was significantly slower in low light than on my 5Dc!

Most of all however, as a carry around everywhere solution, it's big. With the Swivi viewfinder, it's just not unobtrusive or easy to ignore.

Then we hear of this Metabones adapter. I have always liked the IQ of the NEX 7 and in the raw files I can get the IQ very close to that of a 5D3 though the nex has better shadows at the expense of worse noise. Certainly given my benchmark of a 5Dc the IQ is more than sufficient. With the Nex 7 and this adapter I get to use my lenses, whether alt or canon without any focal length multiplication, gain a stop of light to offset the noisier sensor, even get AF with my 16-35L and peaking with all lenses in a tiny and cheap package. I will still have a 5D for when I need to drive my lenses with fast AF and can borrow another if I need a two body event shooting setup however for a carry around or for static work, I get a tiny, cheap and very good package in that NEX 7.

Problem is that there is only one in the country and they won't even put a battery in it for me and there is no return policy. I've never used an EVF of this type and am loathe to invest in one before seeing what I will get with it. Ditto trying the peaking mode. Holding it at least I find it to be a very nice camera.

So, if I want a manual focus solution on a 5D3 I need to spend more and get a bulky package, I could buy a 50L with the 5D3 to get the look I want from my alt lens but that is way out of my budget. Or a nex 7 that I can't even try properly. It is rather frustrating.

Jerome Marot
January 19th, 2013, 01:58 PM
Reading what you wrote about your cameras, I would advise against a NEX-7, particularly with the Metabones adapter. We don't know for sure, but I would be very, very surprised if the AF were usable and the corners had decent sharpness with that combination.

Ben Rubinstein
January 20th, 2013, 06:46 AM
I wish I could decide!

I had decided by late last night to go for a 5D3 and 50L and work around the shortcomings of that lens and the 'focal shift'. About 4am when I couldn't get to sleep I asked myself why I was being so crazy and if I don't shoot events any more, why am I spending the money on a large and heavy pro AF solution? The Nex 7 and my lens would be under half the price of the 5D3 and 50L, plus a fraction of the size and weight, etc. I would still have my beloved 5Dc for use with the AF lenses. This would be a manual focus lens solution only and eminently suited for it and although far from perfect, I can at a pinch use the canon lenses as well, I doubt the lenses IQ with 24 megapixels will be so much worse than on my 5Dc with 12 megapixels.

However, until I can try my lenses out with the peaking and also evaluate the use of an EVF, this is just talk, I'm not investing in a system based on a 'well it sounds good..' :)

Jerome Marot
January 20th, 2013, 07:55 AM
Quite frankly, it would be a miracle if the NEX-7, focal reducer, Canon 50mm f/1.2 combination would give satisfactory results. You are combining an extremely fast lens, a focal reducer fraught with optical problems and one of the most finicky sensors available. This is not going to work.

Besides, the NEX-7 is small and well built, but the viewfinder is not as fine as a ground glass by a large margin, noisy when it's dark, difficult to see with glasses when the sun shines, and with approximative colours and contrast. The user interface is different to anything sensible, the sensor is noisy at high isos and very sensitive to angled rays (meaning very finicky with wide angle lenses, color shifts, extra vignetting, etc...). AF is so slow as to be unusable with Sony lenses and the old adapter (the one using contrast detection) and this is not going to be better with Canon lenses on the Metabone adapter. Peaking may be used, but is not very precise and, in my view, distracting.

This being said, the NEX-7 is small and light. Less so with a 50mm f/1.2 on it, BTW.

Ben Rubinstein
January 20th, 2013, 08:54 AM
Quite frankly, it would be a miracle if the NEX-7, focal reducer, Canon 50mm f/1.2 combination would give satisfactory results. You are combining an extremely fast lens, a focal reducer fraught with optical problems and one of the most finicky sensors available. This is not going to work.

Besides, the NEX-7 is small and well built, but the viewfinder is not as fine as a ground glass by a large margin, noisy when it's dark, difficult to see with glasses when the sun shines, and with approximative colours and contrast. The user interface is different to anything sensible, the sensor is noisy at high isos and very sensitive to angled rays (meaning very finicky with wide angle lenses, color shifts, extra vignetting, etc...). AF is so slow as to be unusable with Sony lenses and the old adapter (the one using contrast detection) and this is not going to be better with Canon lenses on the Metabone adapter. Peaking may be used, but is not very precise and, in my view, distracting.

This being said, the NEX-7 is small and light. Less so with a 50mm f/1.2 on it, BTW.

Hi Jerome,

I think you misunderstand me. The usage with the Nex 7 would be with my Pentax Takumar 50mm 1.4 wide open. Not with a Canon L lens. This 50 year old lens was chosen for its dreamy rendition wide open not modern day sharpness and contrast so that losing 'IQ' does not bother me in the slightest.

I have never been able to focus the Tak accurately on my (actually your!) 5Dc without a viewfinder magnifier used on tripod. This was even with the canon EE-S screen and a Leica R9 split screen, the lens wide open is such low contrast and there is so little DOF that my eyes just cannot do it. With the magnifier and a tripod I can pretty much nail it every time with either of those screens but I cannot manage when shooting handheld. My eye sight is just not up to it.

So I am in a situation where to gain a certain specific 'look' for my photography (f1.4 or faster with significant coma/halation) I can either use a Canon 50L (very expensive and requires a 5D3 to focus accurately), my Canon 50mm 1.4 however the bokeh only 'works' in flat light, it's ugly with specular highlights, or my 50 year old Takumar which has an incredible rendition but requires a solution better than that of the current optical viewfinders. There is one another option, a Leica M with a 50mm summilux pre-asph but as yet I've not decided to sell body parts so as to afford the necessary mortgage! :-)

I believe that peaking and the Takumar is the cheapest and best way to enable the look I am trying to obtain without resorting to using a tripod and magnifier. I have tried the Magic Lantern peaking and it was wildly innaccurate. I would like to test the Sony to see if it is any better with this lens.

From my reading of the white paper and the numerous discussions on various forums including by those who have them and the designer, the IQ loss due to the metabones adaptor does not seem to be close to being 'a focal reducer fraught with optical problems' as you suggest. Could you expand on this point?

I realise the AF will be close to unuseable on the Sony, this does not bother me as it is not what the camera will be used for.

Can you expand also on the sensor being 'finnicky'? I have been working for a while with raw files from the camera that I have downloaded from Imaging Resource and DPReview over various ISO's and lighting. My conclusion is this: The files are slightly noisy even at base ISO however given the room provided by 24 megapixels there is a lot of room for applying default reduction and once you downrez the file a bit it is not IMO an issue. The shadows are a world better than those of the 5Dc, no banding and much more retained detail from significant shadow boosting and after noise reduction. I have to admit that I swore when I first saw just what I could do with those shadows! :-) The tonality is very good with a nice flattish curve as standard, with a carefully curve controlling the lower highlights and a midtone contrast boost I can easily match the 5Dc and come very close to the 5D3. I actually prefer the flatter curve however, it is reminiscent of my 1Ds3. The colour is good, in facial tones I would say even better than canon. I've not done a lot of work with the bright highlights, highlight recovery as the test files provided are usually not blown out but I didn't notice any problems that leapt out at me. I've shot 100,000's of frames with my two 5Dc's over the years, I know what my benchmark 'look' is to a file and I honestly believe that the sony's crop sensor is very very good.

Here is some work shot with the Takumar to give you an idea why I am bothering so much for a $60 fifty year old lens :-)

http://www.getdpi.com/gallery/files/8/9/8/charity_box.jpg

http://www.getdpi.com/gallery/files/8/9/8/the_doorway.jpg

http://www.getdpi.com/gallery/files/8/9/8/ruth.jpg

and a portrait, a field I really want to get into with this lens but have never been able to before as I cannot focus it without a tripod.

http://www.studio-beni.net/dad&carmelle.jpg



HOWEVER. The nex is only an option if I find that the peaking works for me and also if the EVF works for me. I can not tell this till I try it. Otherwise this discussion is all just academic, I will need the more expensive canon solution whether I like it or not.

Ben Rubinstein
January 20th, 2013, 10:00 AM
Decision made. I've been flip flopping over this for ages. I was discussing with my wife what you said about the viewfinder being noisy in low light when she called me into the kids room and told me I had to take a picture. Took me a second to actually see what there was to shoot it was so dark. Camera took a couple of try's to lock focus but when it did I got this at a 1/13 f1.4 iso 3200 in a dark room (just under EV 0) with only a tiny LED nightlight above their heads. There is no way the nex could have given me enough light to manually focus and even if it had the IQ would not have been enough at that iso to take this picture. I'm a pro shooter, not buying a 5D3 for kiddy pics, however it was to me a sign, I need something that can do this at least as well as a 5Dc circa 2005 can. Ordering the 5D3 tonight. Not sure about the 50L yet. Might wait a bit for it.

http://www.studio-beni.net/kids_sleep.jpg

One thing Jerome, you didn't go wrong with that purchase, heck but the 5Dc even today is absolutely incredible!

Jerome Marot
January 20th, 2013, 10:16 AM
Indeed I misunderstood what you were looking for.

You should be able to get focus peaking to work on the NEX-7 with the Takumar. I tried with an old russian lens and with the Sony/Minolta 35mm 1.4 for you (both have relatively low contrast wide open) and it works. You could also appreciate the electronic viewfinder if you have relatively poor eyesight: the reason I don't is mainly because I have very good eyesight.

The dynamic range of the NEX-7 sensor is indeed very good, what I meant is that the sensor is very sensitive to inclined rays. That could be a problem with the focal reducer, since focal reducers work by bending the rays inwards. This is actually your most likely problem: that the focal reducer will cause colour shift and vignetting on the NEX-7. The effect should be smaller on the NEX-6, BTW.

Now, a more general note on the Takumar. I would need bigger samples, but I think that there is another firm who produced lenses with the rendering you are looking for in addition to Leica. It is a firm who collaborated with Leica, actually: Minolta. The irony here is that Minolta AF lenses mount on Sony camera natively and that the present Sony 35mm f/1.4 and 50mm f/1.4 are identical to the original Minolta design. I think that with a Sony A900/A99 and an old Minolta 50mm f/1.4 or 35mm f/1.4, you would get the rendering you are looking for and autofocus. The lenses will also mount on a Nex-7 or Nex-6 with the adapter from Sony (and AF with the second version of that adapter) and, presumably, will also mount on the rumoured future full-frame Nex.

The icing on the cake is that the f/1.4 will be stabilized if you need a picture of your kids.

Ben Rubinstein
January 20th, 2013, 10:21 AM
Hi Jerome,

Not really worth going to another manufacturer and lose compatibility with my other lenses and flashguns if I still have to deal with a DSLR sized body (A900 wouldn't have the iso I would want). That said, would love to see the rendition of that Minolta 50mm wide open if you have a raw file to hand. Always ready to be persuaded :-)

Jerome Marot
January 20th, 2013, 11:59 AM
You are right that the A900 is as big as a full frame SLR, but I was rather thinking about a future full frame NEX camera.

This is the 50mm f/1.4 full open:

http://farm9.staticflickr.com/8092/8399758458_b5befcba39_b.jpg

This is the same (a simple test with a subject at diverse distances):

http://farm9.staticflickr.com/8222/8398668543_9eca8eb13d_b.jpg

This is the same as above, taken with the Nikon 50mm 1.4 G for comparison:

http://farm9.staticflickr.com/8090/8398668875_ae6ac1eb8d_b.jpg

Jerome Marot
January 20th, 2013, 12:06 PM
That would be a portrait in B&W:

http://farm9.staticflickr.com/8371/8399795440_d7e1b20099_b.jpg

Ben Rubinstein
January 20th, 2013, 12:06 PM
I'll worry about the future when I get there :-) Seriously though it looks like we will be waiting at least a year for the FF Nex. That said I see exactly what you mean about the rendition. Especially in the axe shot and the portrait. What is the exact model of that Minolta? Also just a matter of interest, what's with all the axes? :-)

Jerome Marot
January 20th, 2013, 12:30 PM
It is an original Minolta AF 50mm f/1.4 from 1985. As far as I know the present Sony version only has cosmetic changes and revised coatings. You'll find a complete list of Minolta AF and Sony lenses here (http://www.mhohner.de/sony-minolta/lenses.php).

The axes belong to the portrayed man. He builds furniture out of tree trunks.

Ben Rubinstein
January 21st, 2013, 06:09 AM
Just been to my eye specialist, my prescription had changed drastically in the past two years since my surgery and he can make a huge improvement in my eye sight with a new prescription, could be that I might finally be able to focus that 5D after all! We can only hope...

Ben Rubinstein
October 29th, 2013, 04:29 AM
Old thread but with the advent of the new A7r, I'm wondering whether that Minolta lens on that camera might not be a good idea? The limited DR on the 5D3 is driving me crazy at present. What do you think Jerome? Do you have any portraiture shots in RAW I can play with by any chance?

Bart_van_der_Wolf
October 29th, 2013, 04:42 AM
Old thread but with the advent of the new A7r, I'm wondering whether that Minolta lens on that camera might not be a good idea? The limited DR on the 5D3 is driving me crazy at present.

Hi Ben,

Just to point out, the new Sony Alpha A7R requires a Metabones version III adapter (http://www.metabones.com/sony/buy-eos-nex-adapter) for "36x24mm full-frame" coverage, not the 'SpeedBooster' version. It seems like (http://briansmith.com/sony-a7r-field-test/) CaptureOne Pro 7 already supports the A7R Raws (I assume NEX7 Raws are similar, because PhaseOne has not announced formal support for the A7R).

I do not know enough about the Minolta lens to say whether it's compatible with another adapter.

Cheers,
Bart

Ben Rubinstein
October 29th, 2013, 04:49 AM
It should work with the LE-AE1 adaptor made by Sony to provide full features including native autofocus. Apparently. It's a Minolta lens with the same lens protocol as sony lenses.

Cem_Usakligil
October 29th, 2013, 05:28 AM
Old thread but with the advent of the new A7r, I'm wondering whether that Minolta lens on that camera might not be a good idea? The limited DR on the 5D3 is driving me crazy at present. What do you think Jerome? Do you have any portraiture shots in RAW I can play with by any chance?
Are you looking for portraits taken with Nex7 (raw files)? If so, I may be able to help, just let me check my catalog first.

Jerome Marot
October 29th, 2013, 05:58 AM
Old thread but with the advent of the new A7r, I'm wondering whether that Minolta lens on that camera might not be a good idea? The limited DR on the 5D3 is driving me crazy at present. What do you think Jerome? Do you have any portraiture shots in RAW I can play with by any chance?

I am sorry, but I don't shoot many portraits and when I do, I usually cannot publish them online.

The Minolta (or Sony) 50mm f/1.4 in A mount will work with the Sony adapters on the A7 and A7r and autofocus, but you would need the new ones designed for full frame (LA-E3 and LA-E4). But I would advise the SLT adapter (LA-E4), AF is unlikely to be good with the other one.

I am not really sure whether the A7 or the A7r is the best choice. With the kind of rendering you are looking for, 24 mpix is already plenty. Or you could look for a second-hand A99 (or even A900, A850) and gain stabilization. The A99 should come down in price on the used market after the A7 becomes available.

Asher Kelman
October 29th, 2013, 08:21 AM
Ben and Jerome,

I too am very interested in the current fork in the road for DSLR uses. My 5DII has been taken by one son of mine! He needs it! So I ordered a Sony A7R. Still I wonder whether or not a Canon 6D, with more light focus sensitivity, or the 5DIII with water proofing and 7 frames for bracketing would be better. After all, I have so many Canon lenses.

Metabones stresses that AF with their adapters on the Sony system is too slow for prosumer/professional use. For landscapes or fine art reproduction, I see no problem with slowness, but for sure I'd use MF in these cases.

So I'm looking at the offerings of lenses that might take full advantage of the Sony A7R and there are not many available.

Then, in the b.g. of my mind is the strong influence on me that Cem Usakligil moved from Canon to the Nikon D800e. That move really made be stop to think again, as Cem is a very good photographer and particular for fine quality.

Asher

Ben Rubinstein
October 29th, 2013, 08:29 AM
The question as to whether A7 or A7r is an interesting one that I've been musing. I have a 5D3 and a D800e (actually the studio's) so I'm familiar with what is likely to be very comparable 'looks' at the resolution and tonality stage at least.

I do not believe I need more than 24 megapixels resolution - A7
I need a strong camera with pro build - A7r
I do not have or can afford to buy the level of lens needed to achieve the A7r's level of resolution - A7
I would use the better AF of the cheaper camera - A7
The cheaper camera is stupidly cheap! - A7

The reasons to switch to Sony are the better DR, much smaller and lighter. Reasons just to stick with my 5D3 and 50L are the pro level AF, familiarity, flexibility, quiet shutter, system as a whole, chances that canon might get their act together. I have to admit, however much the 50L drives me crazy often and the 5D3's lack of DR is a real pain in the neck, I'm far more tempted to give up on the whole upgrade/switching game. Far too much like hard work and doing it with the first iterations of a new system is not the very best of ideas. My 5D3 now is worth on the second hand market what I paid for it new a year ago (no kidding), I doubt the new cameras will effect its price much as those who would have switched for more megapixels or a lighter weight are not the target market for the 5D3 anyway. I think it's just worth waiting it out a bit.

I'm just thinking out loud, what do you guys think?

Ben Rubinstein
October 29th, 2013, 08:39 AM
Cem thank you for your offer. Do you have any raw samples from this specific lens shot wide open? I have plenty Nex 7 samples from when I was playing with buying that great little camera. Very nice files. Very reminiscent of my 5Dc though far better shadows.

Asher, the new Zeiss lenses for the A7/r are apparently beyond belief, specifically the 55 1.8 which is a summilux beater (so they say) at a fraction of the price. They are expensive but you are getting quality AF zeiss optics and can of course use the other zeiss AF optics which have already been part of the sony system and some of which are very special lenses. The 16-35 and 135mm in particular.

I have the D800e in the studio, never liked Nikon colour and when I compared facial tones from a test of the raws from the A99, 5D3 and D800 I preferred their colour in that order. I would have little doubt that with the sony colour engine the A7r's chip will be rather special. Our D800e in the studio comes rather close to matching our 40 megapixel back's output in everything other than colour. I do not think you would be disappointed whatsoever with the quality of the output of the A7r, if and it's a big if, you make sure to pair it with excellent lenses.

Asher Kelman
October 29th, 2013, 09:37 AM
Thanks Cem and Ben for your insights. I wpuld be very happy with the 55mm Zeiss lens but also need something wide and also equal quality. A 28mm would be important to get people in context of their environment at 10 ft or so.

Asher

Ben Rubinstein
October 29th, 2013, 09:55 AM
http://www.sony.co.uk/product/ddl-carl-zeiss-lenses/sal-24f20z

Jerome Marot
October 29th, 2013, 10:49 AM
The Sony seems to generate lots of excitement... but AF it with Canon lenses is not likely to be really usable. On the NEX-7, contrast AF is not really usable on lenses designed for the A mount. Of course it works with the "translucent" mirror system, but nobody is going to produce an adapter with that system except Sony and for their lenses only. So, basically, one loses AF.

Then there is the electronic viewfinder. I don't find these any good. In any case, they are not a great help for focussing fast lenses: peaking is not very accurate and the resolution is far too low to judge optimal sharpness. I think that the people who swear by them must be using lenses open around f/5.6, then it works. You can ask the display to enlarge the center of the picture for precise focus, but that means working on a tripod and who wants that with a small camera?

About tripods: I find it a real problem that Sony did not include their sensor based stabilization in the NEX line. Not only it is extremely convenient in low light, but having compared the Sony A900 and the Nikon D800 a generally unnoticed advantage of sensor based stabilization occurred to me: the A900 is generally a bit sharper than the D800 when one does not use a tripod. It is a small effect, but it shows that the higher resolution of the D800 (or A7r) is simply going to be wasted. And lens based stabilization adds another problem: it requires one to wait till the lens is stabilized, while sensor based stabilization is simply always on.

As to the Zeiss 24mm f/2.0 (SAL-24f20Z): it is one of the finest lenses available in all mounts, but is designed for the A mount. So it needs to be used on the A900/A99 or with the LA-E4 adapter. It is not compact.

Jerome Marot
October 29th, 2013, 10:57 AM
I have never been able to focus the Tak accurately on my (actually your!) 5Dc without a viewfinder magnifier used on tripod.

Responding to your old post: I realized that the Pentax Takumar 50mm has a 42mm screw mount. Do the AF indicators work when you use the Pentax Takumar 50mm on your Canon camera? If they don't, you may simply need an adapter with a chip to fool the camera. I don't know whether these exist for the EOS mount, but they do exist for the Sony/Minolta A mount. They even enable stabilization then.

(Actually, a quick google check shows that they also exist for the EOS mount.)

Ben Rubinstein
October 29th, 2013, 11:18 AM
I do have an adaptor with a chip and it does provide focus confirmation, accurate focus confirmation with the lens. However it only gives accurate results in good light, in low light it's useless. Added to that due to the AF system on the 5D3 it only activates cross sensor focus points in the middle 3 columns and only the cross sensors are accurate. No doubt due to the low contrast of the lens wide open. I realise this is a fault of the chip, if the chip told the camera it was a specific fast canon lens the problem would not exist.

Jerome Marot
October 29th, 2013, 11:22 AM
However it only gives accurate results in good light, in low light it's useless.

You could put a flash on your camera, not for the flash (which you could disable), but for the AF illuminator.

Ben Rubinstein
October 29th, 2013, 11:27 AM
The idea is for a walk around lens with a certain look. Hardly want to drag a flash around with me to be honest. The camera is bulky/heavy enough.

Cem_Usakligil
October 29th, 2013, 04:16 PM
Hi Ben,

Cem thank you for your offer. Do you have any raw samples from this specific lens shot wide open? I have plenty Nex 7 samples from when I was playing with buying that great little camera. Very nice files. Very reminiscent of my 5Dc though far better shadows.
..
I am sorry but I did not realize that your request was for that specific lens, which I don't have. :(

Ben Rubinstein
October 30th, 2013, 01:51 AM
Thanks anyway!

Asher Kelman
October 30th, 2013, 10:04 AM
Metabones + Dr Brian Caldwell announced their new "Speed Booster",
actually a well known principle from astronomy, a focal reducer or telecompressor.

See here: Metabones - Metabones and Caldwell Photographic introduce Speed Booster (http://www.metabones.com/info/105-info/154-speed-booster)

White Paper is here: http://www.metabones.com/images/metabones/Speed%20Booster%20White%20Paper.pdf

Test is here: An adaptor which claims to make your lens, faster, wider and better!! This is NOT an April Fool’s! | Philip Bloom (http://philipbloom.net/2013/01/13/speedbooster/)

****

Done that before for my sort of photography, see on my BLOG: Photography of the Invisible World: Search results for reducer (http://photographyoftheinvisibleworld.blogspot.de/search?q=reducer)

without reducer/telecompressor:
http://www.pbase.com/kds315/image/142157424/large.jpg

with reducer/telecompressor:
http://www.pbase.com/kds315/image/142157427/large.jpg

overall system changed from f4 to f1.6 and the focal length from 84mm to 34mm!


I must say, I owe you a belated congratulations on using the concept before the Metabones adapter was available. But then, it's hardly surprising, as you understand optics so well and have one of the largest collections of superb specialty lens for UV, IR and visible photography.


The Trade name, Metabones™ distracted me, I must admit, from the fact that you were doing this well before Caldwell's partnership with this company gave them a product! Kudos to you. I should pay more attention to the details of your posts!

:)

Asher

Asher Kelman
October 30th, 2013, 10:23 AM
Now, can we get such focal length reducers that increase the effective aperture using MF lenses on full frame 35mm cameras, like the Sony A7?

Asher

Ben Rubinstein
October 30th, 2013, 10:36 AM
You're not the first to be wondering it however I'm not sure that there is such a great need. The MF lenses in general are either less sharp or stupidly expensive and far less prolific or special/niche/interesting than the 35mm lens market which the speedbooster opened up to those using crop cameras. There are not that many lenses which would be worth the bother to be frank given the native choices already available.

I do have a Mamiya lens adaptor with about 10mm of rise and fall. Never got round to using it though, to be frank, spherical stitching is less bother :D

What I do think there is a market for is adaptors to use large or medium format lenses on a Hcam type board with a mirrorless camera to allow movements for stitching using wider lens circles. Niche, especially in an age of native 36 megapixel cameras, however I have little doubt that Stefan, the man behind the Hcam is thinking about it right now. When I used the camera fusion adaptor the main problem was mirror box shading. The problem was solved with mirrorless crop cameras but it was still a faff. Now with FF mirrorless, the whole concept of flat stitching becomes far more interesting.

Jerome Marot
October 30th, 2013, 10:40 AM
Now, can we get such focal length reducers that increase the effective aperture using MF lenses on full frame 35mm cameras, like the Sony A7?

There is no technical reason why it should not work. There are plenty of commercial reasons why it would be a tough sell. Basically, Metabones can sell their adapter because lots of APS-C users already have plenty of old 24x36 lenses in their drawers.

Asher Kelman
October 30th, 2013, 09:46 PM
You're not the first to be wondering it however I'm not sure that there is such a great need. The MF lenses in general are either less sharp or stupidly expensive and far less prolific or special/niche/interesting than the 35mm lens market which the speedbooster opened up to those using crop cameras. There are not that many lenses which would be worth the bother to be frank given the native choices already available.

Ben,

One does not need "many lenses", LOL. There are some really great MF lenses that could be used and obtainable for a modest price. The increase in MTF will make up for the fact that the lenses might be marginally less sharp than canon's best primes. Also the peripheries will likely take a hit, but for me, thats no issue as I'd like this geometry of edges being less important anyway! If you didn't feel that too, you wouldn't be in love with the Super Takamur Multicoated ~50 mm Pentax lens!

I do have a Mamiya lens adaptor with about 10mm of rise and fall. Never got round to using it though, to be frank, spherical stitching is less bother :D[/quote[ I went for the Pentax 6x7 lenses with the Zörk shift adapter for my 5DII. Again, I have not used it once I discovered how easy it was to take adjacent, overlapping shots handheld.

[QUOTE=Ben Rubinstein;147298]What I do think there is a market for is adaptors to use large or medium format lenses on a Hcam type board with a mirrorless camera to allow movements for stitching using wider lens circles.




What is that board? I have discovered the brilliant Hcam with its ability to take any lens and any MF back, but haven't seen the board you refer to. However, it would be a brilliant tool!

The Fusion adapter is wonderful, but has a lot of slack and I need tape to keep it aligned in the portrait position.

The motorized HCam has gotten my juices flowing!

Asher

Ben Rubinstein
October 31st, 2013, 01:21 AM
Hi,

I was talking about a theoretical hcam type board for mirrorless cameras. I spoke to Stefan from Hartblei last night after writing this but he was rather busy preparing for a roadshow, he did say that the new Sony's were a game changer.

I just don't think there are that many affordable MF lenses which have something that comparibly priced 35mm lenses do not if you are already adapting. The choices are so vast in the 35mm world that there is little in the MF world which would excite in comparison unless you are looking for the larger lens circle or are interested in the more modern and super expensive options which don't have an aperture ring anyway. The one I would love to buy is the RZ 110mm but it is bellow focused, I couldn't focus it on a regular camera. Shame as it has a georgous rendition and feel. I'd love to use it for stitching.

If you are interested in the HCam I can put you in touch with Stefan, super incredibly nice guy who has been a good friend as I learnt the repro business in which he is one of the world experts.

Jerome Marot
October 31st, 2013, 02:33 AM
One does not need "many lenses", LOL. There are some really great MF lenses that could be used and obtainable for a modest price. The increase in MTF will make up for the fact that the lenses might be marginally less sharp than canon's best primes. Also the peripheries will likely take a hit, but for me, thats no issue as I'd like this geometry of edges being less important anyway! If you didn't feel that too, you wouldn't be in love with the Super Takamur Multicoated ~50 mm Pentax lens!

Let me explain why the adapter would not be a commercial success with a simple example.

On APSC-C cameras, people may want to adapt a 35mm f/1.4. The adapter makes this a 24mm f/1.0 lens. It will have the apparent field of view and apparent depth of field of a 35mm f/1.4 on a 24x36 camera. It is f/1.0, so very fast. Photographers fantasize about this kind of mythic aperture values.

Let us suppose that an adapter would exist to adapt medium format lenses on 24x36 cameras. I want to get the same field of view as above, so I would use a 50mm medium format lens. That lens becomes a 35mm with the adapter. So far, so good.

There is one difference, though: 50mm medium format lenses typical aperture is f/3.5-f/4. So, with the huge medium format lens on the adapter, I produce a 35mm with an aperture of f/2.5-f/2.8. It is slower than a typical native 35mm lens. A faster 35mm f/2.0 typically costs less than the metabones adapter and is much smaller, lighter and more convenient.

Remember: medium format lenses are not very fast.

Ben Rubinstein
October 31st, 2013, 02:45 AM
and they're big, not as sharp on a FF sized sensor, don't particularly have any special renderings that you cannot get with a natively 35mm lens, etc, etc.