TIPS & TRICKS No. 5 - Correcting Focus Errors

This thread is part of the Tips & Tricks problematics. See here for more information.

Hi all,

I personal one this time. The image in question was discussed elsewhere on the forum, and it suffers from a slight mis-focus.

So, the purpose of this "tips & tricks" is to suggest ways in which we can try to improve the result. I would normally just delete any photo with this sort of problem, but just occasionally the photo is of importance. In this case, it nicely sets the scene for a photo reportage.

I've performed the RAW conversion and made the resulting TIFF available. Notice that the colour space is ProPhoto, so you'll definitely need need a colour managed application to handle it.

Tim

Bonjour Tim

my try downsized to 800 pix:



My sharpening action at 100% + a noise ninja @50% and sharpen again after downsizing : 80/0.6/0

But sharp image starts with raw, I'd like to start from there instead of a tif...

anyway, as you've already started, the focus is not on the right place, so no miracle possible!

Hi Tim,

I think 'sharp' is a relative term, or it can be. I think you want to move the sharp area (point of the viewer's eye focus). I aimed to get it in the loop/stick/hand area. I selected this area - lasso? - copied selection to a new layer, then sharpened it too much, but used the layer opacity slider to adjust its effect. I then selected the inverse, new layer, blurred that, then a couple more areas for blurring the sheep. I hope my image shows the idea. A bit more care in selecting the areas would be good. However, I am crap at getting things from my screen to the web - maybe that's the subject of your next hint.....

I think, depending on the purpose/size of the final prints, you could get away with it.



Best wishes,

Ray

ot - re Nicolas's sharpening action

Hi Nicolas,

I tried using your excellent sharpening action, but had problems with this image. iirc it was not finding some functions, I think I was trying to use it on selections/layers. (Any chance of a revision - please)

Best wishes,

Ray

Nicolas Claris said:

Bonjour Tim

my try downsized to 800 pix:

Click to expand...

Hi Nicolas,

You've inadvertently bought up an interesting point that's well worth expanding on. I'm sure that most people here already know that the depth of field in a photo is determined by the eye's ability to resolve detail. Only one plane from the subject is truly in focus, either side of this plane the points will be rendered as small discs. The discs get bigger as the object being imaged gets further away from the point of focus.

Now whilst those discs remain small, we see them as points and so they appear to be in focus. This gives us the Depth of Field.

I mention this because there are several things that effect DOF, and many photographers forget some of them. The obvious ones are those relating to the choice of aperture and the length of the lens. However, it's important to realise that the size of the print and the distance of the viewer from the print also play a role.

If the image is printed smaller, so are those tiny discs, and so they become points, and so the DOF is increased. Similarly, moving away from the print does the same thing.

All this to say that yes, reducing the size of the image will increase the Depth of Field.

Tim

Ray West said:

Hi Nicolas,

I tried using your excellent sharpening action, but had problems with this image. iirc it was not finding some functions, I think I was trying to use it on selections/layers. (Any chance of a revision - please)

Click to expand...

It's simple to do the revision and make the action even more versatile.
Just replace the first "Duplicate Background" by "Duplicate current layer" (Layer menu, "Duplicate layer ..." , and then naming that layer to "Sharpened layer").

To even further enhance its versatility, toggle the 'Dialog on' box in front of the two last Smart sharpen activities. One can use an amount of 1 to effectively skip the final sharpening and only use the preceding tone adjustments. One can also replace the last sharpening commands with something else, even another (sharpening) action.

Bart

Thanks Bart

your fully correct!

Thanks Bart - I hadn't pulled apart Nicolas's action, since it worked fine out of the box, in most cases I'd used it on. Your pointers should save me some time.

Best wishes,

Ray

Unfortunately I'm currently on a business trip and I don't have access to my catalogue. Nevertheless, i thought that I'd follow up a little.

I downloaded a trial copy of Focus Magic to see if that would be able to improve the image. Focus magic requires you to specify the amount of correction being applied, and after playing around I realised the different parts of the image require different values.

To get the best result, I corrected the image 3 times, each with a different setting, and then blended the results with the original in Photoshop.

The result is a definite improvement. It doesn't look tack sharp, but I think it may now make an very acceptable A4 print. I'll be trying that once I get back.

The truth of the matter is that unfocused images are impossible to truly rescue in post-processing. However between Focus Magic and some localised sharpening, it is possible to get an acceptable result. Don't expect it to hold up to close scrutinisation however.

Tim

Update: Where there's a will there's a way. I now have a version of the photo with a pin sharp sheep head (although you can't tell in this small version).

Tim Armes said:

Update: Where there's a will there's a way. I now have a version of the photo with a pin sharp sheep head (although you can't tell in this small version).

Click to expand...

Great, Tim! So tell us, how did you do it?

Cheers,

Cem Usakligil said:

Great, Tim! So tell us, how did you do it?

Cheers,

Click to expand...

Well, I'd deleted loads of photos from the shoot, so the first step was to use a file recovery program on the compact flash. Then I looked for a head that both in focus and pointing the right direction.

I pasted the sharp photo on top of the old one and reduced the opacity so that I could see both. This allowed me to scale and move the sharp photo so that the head was overlayed perfectly on the old one.

Then I created a layer mask for the sharp photo and filled it with black (so that you couldn't see it). I put the opacity back up to 100% and then brushed back in the sharp up by painting with white in the layer mask.

Tim

Tim Armes said:

Well, I'd deleted loads of photos from the shoot, so the first step was to use a file recovery program on the compact flash. Then I looked for a head that both in focus and pointing the right direction.

I pasted the sharp photo on top of the old one and reduced the opacity so that I could see both. This allowed me to scale and move the sharp photo so that the head was overlayed perfectly on the old one.

Then I created a layer mask for the sharp photo and filled it with black (so that you couldn't see it). I put the opacity back up to 100% and then brushed back in the sharp up by painting with white in the layer mask.

Tim

Click to expand...

Ah, nothing autoMagical then <smile>. Just the good old compositing using layer masks. Well, it's a good thing we have those recovery programs after all, don't we ;-).

Cheers,

Nicolas Claris said:

My sharpening action at 100% + a noise ninja @50% and sharpen again after downsizing : 80/0.6/0

Click to expand...

Aloha Nicolas. I must have missed earlier discussion regarding your sharpening action.

Am I understanding correctly that you created a PS action for sharpening needs? Could you point out where it is detailed? Thank you.

-Scott

Aloha Scott

Yes, you can download it here

Links to some discussions:

http://www.openphotographyforums.com/forums/showthread.php?t=3274&highlight=sharpening+action


http://www.openphotographyforums.com/forums/showthread.php?t=3013&highlight=sharpening+action

http://www.openphotographyforums.com/forums/showthread.php?t=2471&highlight=sharpening+action

http://www.openphotographyforums.com/forums/showthread.php?t=2621&highlight=sharpening+action

Enjoy

Thank you Nicolas... I've got a few images from last night's efvent where the 1Ds focused where I didn't expect!

A quick trial shows some hope. -Scott

Here is an interesting plugin that will let you focus on different parts of your image using depth maps. Blurring surrounding areas often makes an out of focus object look sharper.

Click any chessman to change the DOF
http://www.dofpro.com/interactive1.htm

http://www.dofpro.com/

You can do a similar edit with Lens Blur but you need to make a map.

Hi Chip,

The DOFPRO software is interesting especially for movie makers. However, for photoshop users, we need to get a depth map which we have to create by hand. So why not just do what I already do, a series of blurring excluding the plane of maximum focus and giving most blur to the most distant areas?

What's so special about this plugin that we can't do fast by hand?

Asher

Anyway, this plugin does not focus defocussed areas, AFAIK, just blurs in zones, it seems.

Asher Kelman said:

Hi Chip,

The DOFPRO software is interesting especially for movie makers. However, for photoshop users, we need to get a depth map which we have to create by hand. So why not just do what I already do, a series of blurring excluding the plane of maximum focus and giving most blur to the most distant areas?

What's so special about this plugin that we can't do fast by hand?

Asher

Anyway, this plugin does not focus defocussed areas, AFAIK, just blurs in zones, it seems.

Click to expand...

I thought some might find it interesting. It definitely isn't the fastest way to go...and like I said, you can do the same with Lens Blur's Depth Map (the plugin has more options).

Another trick besides extracting and pasting is to blur the surrounding area. Sometimes this tricks the eye into seeing the subject in focus.

Chip,

I should have thanked you for introducing me to the plugin. If I was doing movies, I'd think of this software since it can key and track changes over a large number of frames.

Asher