The 1.5m Planoconvex is normal (not reversed) orientation worked best for the ZM 28mm on my Sony A7Rii.
I did try it reversed, but this did not work as effectively.
Fred Miranda wrote:
Did you try the 1.5m PCX filter normal or reversed on the ZM 28?
@HaruhikoT@@ wrote that it worked best for his G28/2.8 (in reverse orientation) but they probably have different exit pupil distances.
I see from earlier threads that you preferred the 1m Zeiss Proxar for the ZM 28 instead. Is that still the case? If so, how did you attach it to the lens?
Thanks for being a continuos source of useful information, Candreyo. I'm interested on the ZM25 and, if I recall correctly, you said that a 1m. Proxar was the best match for this lens. Did you try also the 1.5m Plano convex.?. So far, it seems that PC elements work better than meniscus close-up lenses. I wonder why the Biogon ZM25 is different, in this aspect, from the G21, G28 or ZM28..
The 1.5m Planoconvex is normal (not reversed) orientation worked best for the ZM 28mm on my Sony A7Rii.
I did try it reversed, but this did not work as effectively.
Thanks Candreyo,
So, just to confirm. From your infinity tests, a 1.5m PCX (not-reversed) yielded better corners than the Proxar 1m with the ZM 28/2.8+A7RII. Correct?
With the 1.5m PCX, did you have remove any shims from the lens to reach infinity? If so, how many?
Slalom wrote
Hi with the G21 which Mount are you using and did you have to Hack the rear as for Techart TA-GA3?
My G21 has a Contax G mount and I was using the Techart TA-GA2 Contax G AF adapter and I made no changes to the lens or adapter except to use the G21 on my NEX-7 a few years ago I removed the lens standing feet from the rear of the lens. I believe the only difference with the TA-GA3 to the TA-GA2 is the newer adapter has Bluetooth for updating the firmware.
As some of you have noticed finding the solution for a specific lens in a thread like this is not that easy in retrospective.
I have closely worked with HaruhikoT (who also allowed me to use his photos and data) and put together this article: https://phillipreeve.net/blog/rangefinder-wide-angle-lenses-on-a7-cameras-problems-and-solutions/
listing again the problems that might occur when using RF WA lenses on A7 series cameras but also the possible solutions.
By this article I hope to increase the reach of this topic and get more people in the boat,
so we can further investigate this and find the best possible front filter solution for many more lenses.
In case you have anything to share, like a good working front filter solution for a lens not yet included,
how to mount a glass element to a specific lens, a before/after comparison or anything else I would love to hear from you and extend the article.
I believe there's a small mistake, though. The article recommends a 2m. Proxar for the Biogon ZM25 but, quoting one of candreyo's posts :
" for those that want to correct the 25mm ZM Biogon, I have found that a 1m Proxar works best. Equally, I would assume that a 1000mm Planoconvex lens from OptoSigma would work just as well,.. "
Hi Fred,
Correct , a 1500mm Plano Convex worked best on the Zeiss 28mm ZM lens, not reversed.
I had to remove 2 internal brass shims to allow it to reach infinity ( and equally allow rangefinder focus to work properly).
I held the lens in place with a 46mm to 55mm step up, then a 55mm to 52mm step down, placed the lens inside the 52mm inner diameter of the 55 to 52mm step down, then held it in place with a 52mm retention ring from a disassembled 52mm UV filter.
Fred Miranda wrote:
Thanks Candreyo,
So, just to confirm. From your infinity tests, a 1.5m PCX (not-reversed) yielded better corners than the Proxar 1m with the ZM 28/2.8+A7RII. Correct?
With the 1.5m PCX, did you have remove any shims from the lens to reach infinity? If so, how many?
I believe there's a small mistake, though. The article recommends a 2m. Proxar for the Biogon ZM25 but, quoting one of candreyo's posts :
" for those that want to correct the 25mm ZM Biogon, I have found that a 1m Proxar works best. Equally, I would assume that a 1000mm Planoconvex lens from OptoSigma would work just as well,.. "
Correct, a 1m Proxar or 1000mm OptoSigma Planoconvex lens seems to work best on the Zeiss 25mm ZM lens. The correction lens is being used as standard, not reversed.
A 1500mm lens does work some, but I have found a 1000mm lens to work better on the 25mm ZM
I'm not sure why the Zeiss ZM 25mm behaves differently then the Contax G line or the ZM 28mm.
I have tried a 1.5 Planoconvex on it, and it did work some to correct the corners, but a 1m Proxar worked even better.
I do know that the ZM line of lenses are not clones of the Contax G line, but completely new computations. I do recall also that the 25mm ZM Biogon was reported to have the sharpest MTF graphs for a lens in this focal length when it was released.
Maybe whatever Zeiss has done to create the 25mm ZM, it shares less of that pedigree with its Contax G predecessor or 28mm sibling, and more of an all new Zeiss design.
artur5 wrote:
Thanks for being a continuos source of useful information, Candreyo. I'm interested on the ZM25 and, if I recall correctly, you said that a 1m. Proxar was the best match for this lens. Did you try also the 1.5m Plano convex.?. So far, it seems that PC elements work better than meniscus close-up lenses. I wonder why the Biogon ZM25 is different, in this aspect, from the G21, G28 or ZM28..
candreyo wrote:
Hi Fred,
Correct , a 1500mm Plano Convex worked best on the Zeiss 28mm ZM lens, not reversed.
I had to remove 2 internal brass shims to allow it to reach infinity ( and equally allow rangefinder focus to work properly).
I held the lens in place with a 46mm to 55mm step up, then a 55mm to 52mm step down, placed the lens inside the 52mm inner diameter of the 55 to 52mm step down, then held it in place with a 52mm retention ring from a disassembled 52mm UV filter.
Thank you!
it look like I am going to dust off my ZM 28! I just ordered the 1.5m PCX for it. I'm expecting to get both the 1.5 and 5m PCX (for the ZM 35) lenses on Jan 10th.
Fred Miranda wrote:
Thank you!
it look like I am going to dust off my ZM 28! I just ordered the 1.5m PCX for it. I'm expecting to get both the 1.5 and 5m PCX (for the ZM 35) lenses on Jan 10th.
Ooh looking forward to some interesting 28mm comparisons in the new year....
I just ordered and paid for the 5m for the ZM 35. I said whatever Fred ordered I want . Lol
Did not know about the 28
Fred Miranda wrote:
Thank you!
it look like I am going to dust off my ZM 28! I just ordered the 1.5m PCX for it. I'm expecting to get both the 1.5 and 5m PCX (for the ZM 35) lenses on Jan 10th.
GMPhotography wrote:
In all this got a little lost on TAP usability with the ZM 35 1.4 and the PX5. Can I still use the TAP
It will work fine with TAP. (But I'm not 100% sure if TAP will allow focus at infinity distance)
I should be able to test both ZM 28/2,8 and ZM 35/1.4 with their respective filters on Jan 10th.
Fred
Has anyone tried a PCX lens on the CV 15MM III and A7R2? Opto Sigma offered to make a PCX lens to spec. Based on what I've read on this site I am guessing an SLB-56-1500 might work, but that is only a guess, not sure if 1500 would be the optimum focal length. 56mm should fit inside a 58mm filter ring for mounting. Any suggestions will be appreciated.
Bradford wrote:
Has anyone tried a PCX lens on the CV 15MM III and A7R2? Opto Sigma offered to make a PCX lens to spec. Based on what I've read on this site I am guessing an SLB-56-1500 might work, but that is only a guess, not sure if 1500 would be the optimum focal length. 56mm should fit inside a 58mm filter ring for mounting. Any suggestions will be appreciated.
A good copy of the CV 15/4.5 is very sharp to the corners wide open on the A7RII. I don't think this lens needs any help.
