David Ellsworth
Well-known member
Autofocus confirm chip for Canon EOS
Paul Corfield informed me that such a thing as an AF confirm chip existed, and could be bought on ebay (thanks, Paul). I bought the "*EURO* ETTL AF Confirm Programmable Chip for Canon EOS" from the vendor "tagotech" (not sure if this is the best one; it's just the one I chose). This is for use with my new scope, the Explore Scientific 127mm triplet, with Televue RFL-4087 0.8x reducer.
I bought this chip mainly for the EXIF info (programmable focal length) and to fix problems the 40D and 450D have when there are no lens electronics (dark Live View exposure preview in 'M' mode, and the need to tape teleconverter pins). The focus confirmation is nice but I can do without it.
The AF confirm chip arrived today (it came from Singapore). It appears to be rugged and well-made, and it's easy to place in the proper spot using the provided template as a guide. (Ironically I didn't use the template because I didn't read the instructions until after gluing — I didn't know that thing was a template; I did the measurements manually, but they agreed quite well with the template afterwards.) Incidentally, the template appears to have been made using a 3D printer.
The bayonet adapter with chip glued on attaches satisfyingly to my camera. I was worried because at first, it was resisting strongly against my putting it on and I thought maybe I had glued it at too high a height, but then subsequent attachments of the bayonet adapter had just the right amount of resistance and click in satisfyingly. (I glued it on so the base of the chip was a hairline above the top of the bayonet.)
Focus confirmation works great, as long as I start with focus too NEAR (racked outward beyond proper focus) and rack the focus inward (towards the FAR direction) until the focus confirmation light activates. My initial impression is that this gives me focus just as perfect as if I had done it using Live View at 10x magnification. However — if I try to focus by being too FAR and focusing in the NEAR direction until the light activates, then focus is WAY off. Maybe that's because my scope with reducer is f/5.94 and not f/5.6, or maybe it's because of the scope's soft focus of violet; I don't know at this point.
The really great thing is that since the chip is reporting an aperture and focal length, my 40D is no longer confused about Live View exposure simulation! In 'M' mode the Live View exposure preview is exactly correct and I no longer need to futz around with switching to 'A' mode to focus then back to 'M' mode to take a shot.
I keep my 40D in AI Servo mode by default, using the special * button to focus instead of half-pressing, but AI Servo is apparently incompatible with focus confirmation. I have to switch to One Shot focus for focus confirmation to work (though I can still use the * button to do it).
This chip has a neat feature, in that you can program it to be either in AF mode or MF mode (and AF mode is the factory default); in AF mode, you can fully hold the shutter button and then have the shot taken only when you reach proper focus. This may be good for birds in flight. (It works whether AF is set as the * button or as half-pressing.)
I programmed the chip to be at f/5.6 (focus confirmation doesn't work at f/6.3), and programmed it to report a focal length of 755mm, because I've measured the Televue RFL-4087 reducer to be about 0.793x or 0.792x.
The only shortcoming of this chip that I'm aware of is that microfocus adjustment goes from 01 to 17 (default 09), and some other chips available on ebay apparently have 32 levels of microfocus adjustment. It would also be nice to have three extra pins for teleconverter communication, so the chip could automatically multiply its programmed focal length by 1.4 or 2.0, and multiply the aperture as well with a programmable maximum of f/5.6 or f/8 (depending on whether you have a 1-series body) or no maximum (if you don't mind losing AF confirmation) — but I don't think any of the chips available have this feature. (Heck, I wish that Canon had designed its TC communication protocol so that stacked TCs were properly EXIF'ed.)
I am going to order a second AF confirm chip to glue onto my T adapter so I can get proper Live View exposure simulation at 952.5mm (with no reducer, and optionally with teleconverters) and focal length in the EXIF. (Of course it'll have to be rounded to 952mm for this, as only integer focal lengths can be programmed — despite the fact that I've measured my scope to be 952.5mm plus or minus 0.1mm.)
Paul Corfield informed me that such a thing as an AF confirm chip existed, and could be bought on ebay (thanks, Paul). I bought the "*EURO* ETTL AF Confirm Programmable Chip for Canon EOS" from the vendor "tagotech" (not sure if this is the best one; it's just the one I chose). This is for use with my new scope, the Explore Scientific 127mm triplet, with Televue RFL-4087 0.8x reducer.
I bought this chip mainly for the EXIF info (programmable focal length) and to fix problems the 40D and 450D have when there are no lens electronics (dark Live View exposure preview in 'M' mode, and the need to tape teleconverter pins). The focus confirmation is nice but I can do without it.
The AF confirm chip arrived today (it came from Singapore). It appears to be rugged and well-made, and it's easy to place in the proper spot using the provided template as a guide. (Ironically I didn't use the template because I didn't read the instructions until after gluing — I didn't know that thing was a template; I did the measurements manually, but they agreed quite well with the template afterwards.) Incidentally, the template appears to have been made using a 3D printer.
The bayonet adapter with chip glued on attaches satisfyingly to my camera. I was worried because at first, it was resisting strongly against my putting it on and I thought maybe I had glued it at too high a height, but then subsequent attachments of the bayonet adapter had just the right amount of resistance and click in satisfyingly. (I glued it on so the base of the chip was a hairline above the top of the bayonet.)
Focus confirmation works great, as long as I start with focus too NEAR (racked outward beyond proper focus) and rack the focus inward (towards the FAR direction) until the focus confirmation light activates. My initial impression is that this gives me focus just as perfect as if I had done it using Live View at 10x magnification. However — if I try to focus by being too FAR and focusing in the NEAR direction until the light activates, then focus is WAY off. Maybe that's because my scope with reducer is f/5.94 and not f/5.6, or maybe it's because of the scope's soft focus of violet; I don't know at this point.
The really great thing is that since the chip is reporting an aperture and focal length, my 40D is no longer confused about Live View exposure simulation! In 'M' mode the Live View exposure preview is exactly correct and I no longer need to futz around with switching to 'A' mode to focus then back to 'M' mode to take a shot.
I keep my 40D in AI Servo mode by default, using the special * button to focus instead of half-pressing, but AI Servo is apparently incompatible with focus confirmation. I have to switch to One Shot focus for focus confirmation to work (though I can still use the * button to do it).
This chip has a neat feature, in that you can program it to be either in AF mode or MF mode (and AF mode is the factory default); in AF mode, you can fully hold the shutter button and then have the shot taken only when you reach proper focus. This may be good for birds in flight. (It works whether AF is set as the * button or as half-pressing.)
I programmed the chip to be at f/5.6 (focus confirmation doesn't work at f/6.3), and programmed it to report a focal length of 755mm, because I've measured the Televue RFL-4087 reducer to be about 0.793x or 0.792x.
The only shortcoming of this chip that I'm aware of is that microfocus adjustment goes from 01 to 17 (default 09), and some other chips available on ebay apparently have 32 levels of microfocus adjustment. It would also be nice to have three extra pins for teleconverter communication, so the chip could automatically multiply its programmed focal length by 1.4 or 2.0, and multiply the aperture as well with a programmable maximum of f/5.6 or f/8 (depending on whether you have a 1-series body) or no maximum (if you don't mind losing AF confirmation) — but I don't think any of the chips available have this feature. (Heck, I wish that Canon had designed its TC communication protocol so that stacked TCs were properly EXIF'ed.)
I am going to order a second AF confirm chip to glue onto my T adapter so I can get proper Live View exposure simulation at 952.5mm (with no reducer, and optionally with teleconverters) and focal length in the EXIF. (Of course it'll have to be rounded to 952mm for this, as only integer focal lengths can be programmed — despite the fact that I've measured my scope to be 952.5mm plus or minus 0.1mm.)
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Re-framing on the fly was not possible, because I had to put the tripod on the very edge of my balcony to get a good view of the hawk, and this was an awkward angle to put my head down to the viewfinder, so I used Live View. (Probably I need a right-angle viewfinder.)
