06-22-2010, 10:52 AM
Hi Geno,
[quote name='genotypewriter' date='22 June 2010 - 05:49 AM' timestamp='1277178571' post='648']
Hi Wim,
Yes, you're right. I actually meant to say multiple shims for each corner (like there is on the sensor mount?)./quote]
Ah, ok. No I don't think those are available. You'd have to construct those yourself I am afraid.
quote]I got this IR modded 50D and VF is completely off. The AF works fine for most lenses (partly thanks to micro-adjust) but I want to shim the focusing screen properly to make it consistent with the sensor. I know this is a big can of worms because different lenses focus IR different points so there's no one right place to pick. But I have the 200 f/2 which needs no correction for IR (it's the most APO lens out of all the [url="http://forum.photozone.de/index.php?/user/10892-genotypewriter/page__tab__aboutme"]ones I've used[/url]) and I want to be able to MF through the VF on that because the AF "correction" done to ensure proper IR focusing for my other lenses is so heavy that not even full microadjust is enough to get the 200 to AF.
I know there are multiple shims in there but I've been too chicken to meddle around in case I break something. I've already changed the focusing screen to the S type but that's all. Any ideas on how to pull those shims out? (I might actually need to add instead of remove... can't remember the error).
Thanks...
[/quote]
I would think you would get backfocus errors (longer wavelength and hence focuspoint). So probably removing shims to lengthen the pathway to the focusing screen, which might be difficult, because it could well be there aren't enough shims to take away. Considering the differences between lenses, a can of worms is indeed an apt description.
However, what you could do in order to get a good visual idea, is to adjust the diopter setting. However, this would again be different for each lens, so a lot of work to figure out...
Another option would be a thinner focusing screen, but then you have the problem on how to make sure it will still be clamped in properly, plus that you need different thicknesses for different lenses...
In short, I think the simplest and easiest way likely is to figure out the different diopter settings on the VF for each lens, and do MF with the -S type screen <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />.
Kind regards, Wim
[quote name='genotypewriter' date='22 June 2010 - 05:49 AM' timestamp='1277178571' post='648']
Hi Wim,
Yes, you're right. I actually meant to say multiple shims for each corner (like there is on the sensor mount?)./quote]
Ah, ok. No I don't think those are available. You'd have to construct those yourself I am afraid.
quote]I got this IR modded 50D and VF is completely off. The AF works fine for most lenses (partly thanks to micro-adjust) but I want to shim the focusing screen properly to make it consistent with the sensor. I know this is a big can of worms because different lenses focus IR different points so there's no one right place to pick. But I have the 200 f/2 which needs no correction for IR (it's the most APO lens out of all the [url="http://forum.photozone.de/index.php?/user/10892-genotypewriter/page__tab__aboutme"]ones I've used[/url]) and I want to be able to MF through the VF on that because the AF "correction" done to ensure proper IR focusing for my other lenses is so heavy that not even full microadjust is enough to get the 200 to AF.
I know there are multiple shims in there but I've been too chicken to meddle around in case I break something. I've already changed the focusing screen to the S type but that's all. Any ideas on how to pull those shims out? (I might actually need to add instead of remove... can't remember the error).
Thanks...
[/quote]
I would think you would get backfocus errors (longer wavelength and hence focuspoint). So probably removing shims to lengthen the pathway to the focusing screen, which might be difficult, because it could well be there aren't enough shims to take away. Considering the differences between lenses, a can of worms is indeed an apt description.
However, what you could do in order to get a good visual idea, is to adjust the diopter setting. However, this would again be different for each lens, so a lot of work to figure out...
Another option would be a thinner focusing screen, but then you have the problem on how to make sure it will still be clamped in properly, plus that you need different thicknesses for different lenses...
In short, I think the simplest and easiest way likely is to figure out the different diopter settings on the VF for each lens, and do MF with the -S type screen <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />.Kind regards, Wim
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....