A7R thin filter modification
As we all know, older lenses were designed for film cameras. The ray path of each lens is designed to "hit" precisely on the plane of the film. But unlike film cameras, digital cameras must have a piece of optical glass, known as IR-filter, installed in front of the sensor. Its function is to protect the sensor and filter out invisbile IR-light. The result is: when we use legacy lenses on digital sensors, the optical path, which originally designed for film, would inevitably be changed due to the existence of IR filter in front of the sensor that leads to degradation of optical performance. Since the degradation is related to the ray angle, the larger the incident angle, the more severe the degradation will become. Roger Ciacala of Lensrentals first discussed this issue in 2014 (http://www.lensrentals.com/blog/ ... -and-adapted-lenses). Also Lloyd Chamber of Diglloyd (http://diglloyd.com/blog/2015/20 ... d-lensBehavior.html)For rangefinder cameras, since the flange distance is significantly shorter than the SLR's, the ray angle, especially for wide lenses, would be even more extreme, resulting in particularly bad result in corner performance, which commonly known as "smearing." Leica solved (or at least alleviated) this problem by installing particularly thin IR-filters in their cameras, particularly the M8 and M9. This is why many have argued that Leica cameras yield better result than Sony cameras even with the same lens.
If the question is related to the filter thickness, what if we replace the filter of an 36MP A7R with a thin one in order to maximize its resolution power with legacy lenses?
Roger Ciacala also ran some tests here:
http://www.lensrentals.com/blog/2015/01/a-thinner-sensor-stack
mostly affected are edges and corners of wide angle lenses, at infinity.
read that the improvement is substantial, mind posting some 21/24/28mm shots? M3fans 發表於 2015-8-25 21:04
mostly affected are edges and corners of wide angle lenses, at infinity.
read that the improvement i ...
X2 {:4_134:} the weather was so unpleasant in recent weeks, didn't do much shooting.
will do later :D This is by Voigtlander 28mm f/2. Sorry for the noise. It was shot at ISO 4000.
https://farm1.staticflickr.com/566/20253500783_a938e444d8_h.jpg
large file Jason 發表於 2015-8-25 23:56
This is by Voigtlander 28mm f/2. Sorry for the noise. It was shot at ISO 4000.
Interesting indeed...it seems like the filter glass replacement cure the "UFO lights reflections" as well. It has long been argued that those weird reflections at point light source is a result of sensor internal reflections. It was taken by Voigtlaender 15mm v2. with flatfield plugin applied.
this pic doesn't do justice of the real performance, as it was shot through a glass. There is reflection in the middle of the pic.
Please see the large file for details, particularly for the roof of Kowloon Masjid.
https://farm1.staticflickr.com/703/20712077618_19b02ebfec_h.jpg
large file it is great to see 1st hand experience here, thanks jason for sharing this
I've tracked information on the modification for some time and very positive opinion seen
I guess you have the humidity and corrosion resistant glass version, mind sharing how long did it take? Hi Jason Ching, thanks for your sharing. Could you tell me where I can get this modification for my A7R? 本帖最後由 Jason 於 2015-8-28 00:07 編輯
M3fans 發表於 2015-8-27 18:52
it is great to see 1st hand experience here, thanks jason for sharing this
I've tracked information...
you are very welcome, M3fans.
yes. i specifically asked for anti-humidity/corrosion glass for the modification. we need that in hk.
the modification process, actually, was not exactly smooth....though, finally, im pleased with the result.
i do indeed think the modification makes a substantial improvement. it is worth every penny. I'm now even considering getting an A7RII to mod it. Canerzi 發表於 2015-8-27 20:59
Hi Jason Ching, thanks for your sharing. Could you tell me where I can get this modification for my...
Hi Canerzi hing,
you may search "Kolari vision" for more information. the cost of modification with round-trip shipping is around 4000 HKD. Jason 發表於 2015-8-28 00:06
you are very welcome, M3fans.
yes. i specifically asked for anti-humidity/corrosion glass for the...
the results are very positive as demo by your pictures
A7rII mod will be very attractive, they are working hard on it, hope that it will be offered officially soon 同場加映 A7RII + VM15mm v2.
ISO 1600 乾淨到不得了！
https://farm1.staticflickr.com/699/20808932179_33dd6fcf3a_b.jpg
large file 如果A7RII有得改，费用又差不多，
計落好過买M240...除左冇RF之外...
自已毒自已咋！;P bubu 發表於 2015-8-30 18:37
如果A7RII有得改，费用又差不多，
計落好過买M240...除左冇RF之外...
EVF影实物好，影人就...尤其是MM...慢! bubu 發表於 2015-8-30 18:37
如果A7RII有得改，费用又差不多，
計落好過买M240...除左冇RF之外...
已可改.... 但要多USD100 ...
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