Dedicated SB for low-light Autofocus ?

I have had my Pentax FA 50mm 1.4 for a couple of weeks now. I am really pleased with how flexible low-light shooting has become with this lens.

However, I have a black cat. =D

The system is forever trying to figure out how to focus on this black cat in low light., and because there are almost zero contrasting lines on this black cat, it will continue to trying without success.

I had an idea last night. Included with the shipment of the 50mm was an AF 540 FGZ dedicated flash unit with SB mode. So I decided to try it out, and it worked perfectly! I was able to use the autofocus in very low light (with help from the auto focus assist lamp on the flash) and get some pics of my kitten that I was unable to get before.

Now, the AF 540 FGZ is not small and it got me thinking. Does anyone now of or think they would use a small unit that is not a flash, but rather just a dedicated "SB" unit that simply serves as an autofocus assist lamp?

Also, please forgive me if I'm using the "SB" term in some improper way... I don't know what it means but would like to!?

Thanks for any info.

Hi Ed,

You could try a laser pointer. I guess the af is like others, relies on sharp/contrast areas. If you got one of the keyfob types, you may be able to mount it on the camera, and adjust it so the spot was at the right place, or may be easier with a different pattern. However, it will be trial and error, getting one bright enough to show up, but not too bright to singe the fur.... ;-)

Best wishes,

Ray

So, what you're saying is... no.

Why isn't the autofocus assist lamp standard on cameras ?

Is it viewed as admitting to a weakness by the designers ?

Is there some other solution I'm not aware of ?

Usually when I think about something I'd like, the marketplace has anticipated my need and its available, even if for another brand. I'm surprised this is not something that other's would like. It seems most DSLRs do NOT have an autofocus assist lamp...

I think it would be nice as an option.

It is curious that this feature (focus assist lamp) is found on a high percentage of point and shoot cameras, yet is almost non-existent on DSLRs, I have have considered many rationalizations as to why it isn't built into the DSLRs, but in the end I do not know for sure why it has been omitted. I have thought that since most of the newer flashes have the SB focusing assist on them that there is obviously some way for the camera to use the flash's hot shoe to do this without using the flash it's self. This gave me the idea that it would be pretty slick if someone could develop a small SB device that attached to the hot shoe, and by default made the camera think it was a flash unit in the SB mode. It could be pretty small, say 1"x1"x2", or something like that, and run on an "N" size battery (or similar). It would be a lot less cumbersome than having a full size flash unit on it when shooting in low light. Anybody out there want to invent one for me? :>)

Kyle

Re Laser suggeston:

I would be very concerned about using a laser on ANY animate object. Lasers can do serious eye damage. If a person or an animal moves unexpectedly you could do some serious damage and have a nice lawsuit on your hands from the person or the animal's owner.

A dedicated focus device would be the way to go. Pentax or any accessory manufacturers listening?

David

Very Close from Nikon

Here is a product from Nikon that very nearly fills the bill - in fact, I assume this could be modified to get rid of the cord so it could be used to just enable very low-light autofocus...


http://www.microglobe.co.uk/catalog/images/niksc29.jpg