Zplusc3 wrote:
What is the combination you are using to hold the PCX?
I'm using a 55-52 step down ring with the PCX 1500 held by 2 filter holder rings.
The filter holder rings were taken from a Tiffen 52mm UV filter, I think others have used the AmazonBasic 52mm uv filter.
The PCX is held as close to the inside as possible. I think the filter holder ring is screwed in like 1 rotation in to the 55-52 step down.
With this PCX assembly on the G21 used on A7III I don't see any added vignetting.
Initially I used a filter holder ring for the inner side and a 52-58 step up on the outer side to hold the PCX but this combination was introducing some vignetting.
On the G28 I have a 46-55 step up ring so I can swap the PCX assembly between the two. ...Show more →
I have the PCX inside a 52mm Kenko CPL blank(thick). Anything thinner and the ND+CPL thread will not mount.
You must have one thick step down ring if it can take 2 filter holders and the PCX and still have thread left for a ND/CPL/Step Up add on. I just tried this approach with my 55-52 Rise-UK step down and ended breaking my 52 holder ring(thread ran out & snap).
I have had no vignetting issues using:
° thin 52UV filter setup OR
° with inside lens(G 21) PCX mounting OR
° with a carpet tape makeshift ring/pad to mount PCX inside 55mm filter
However I am looking for a single common solution for both G 28 & 21 with clean fit, perfect centering and ND/CPL/Hood adaptability.
New FD adapter arrived today. Unfortunately no change on the infinity focus for the G 28.
Strangely, without PCX mounted. the 28 lens easily focuses way beyond 'infinity'.
But with PCX mounted, it falls way short.
This is barely the case on the G 21 where infinity focus with and without PCX are very very close. Also I had only 1 shim in the G 21 to take off.
Since it was 3 shims(2 brass+1 copper) that I had taken off on the G 28 and also with infinity focus gap with & without PCX appearing so large, wonder whether adding 1 copper shim back might improve/fix this issue(though logically should not work with decreased fd).
Please add your comments/suggestions on any similar experiences with PCX and shimming on the Zeiss, Voight glass.
Thanks
-lestor
I recently bought an old CV Heliar 12mm 5.6, its the old M39 version. After initial testing on the Sony A7RII at least wide open I saw similarities to the G21 without PCX filter when it comes to field curvature and astigmatism.
So I tried to make some further tests while holding a 1500mm PCX filter in front of the Heliar. It works very well!
Now I have a question, can a PCX filter be rear mounted or is it optically necessary that the filter has to be in front of the lens? I ask because the 1500mm version is only available in 50mm and 30mm diameter and the normal 50mm filter that is used on G21 and G28 can not cover the front of the Heliar.
Mathieu18 wrote:
Glad it’s working. Have to get yourself another PCX to fix the vignette and you’re good to go.
Did the new adapter help?
Finally have a common PCX mount solution for both the Contax G 21 & G 28(on Nikon Z6) :
Setup as follows:
° Opto Sigma 1500 PCX lens reverse mounted inside 55mm Kenko UV blank
° 1.5mm rubber ring/wide-band for centering
° locked down using 55mm - 67mm step up ring.
° 67mm K&F fader vari ND & CPL 2in1 filter (went with this approach as stacking ND and PL filters gave hard vignetting)
Step up(55-67) locking ring with rubber-ring/band(centering) visible
55mm Kenko UV blank holder for PCX.
mounted setup without filters
mounted setup with ND + CPL filter
Early impressions
°PCX corrections observered
°No hard vignetting seen on either lens and even with a 2in1 ND + CPL mounted.
°Moderate darkening seen on the G 21 at F11 and higher with ND/CPL filter mounted (should be manageable in PP with flat field, corner fix or similar S/W plugins - will be testing this in the next few days).
PS:After some grinding/polishing on the FD adapter, the G28 now attains infinity on the Z6 with PCX mounted.
Minor finishing detail to complete and can then share results here.
I ask for this reason: I recall someone trying one that should help and finding it didn't.
But then I realised: they were hoping for a sharper outer field. And of course they were disappointed because, well the lens doesn't really offer that, even natively.
But reducing the FC could well improve the bokeh (which is what the lens does offer) an it might be worth trying!
I ask for this reason: I recall someone trying one that should help and finding it didn't.
But then I realised: they were hoping for a sharper outer field. And of course they were disappointed because, well the lens doesn't really offer that, even natively.
But reducing the FC could well improve the bokeh (which is what the lens does offer) an it might be worth trying!
It looks like the interest for PCX solutions diminish a lot because we have some many native options now.
Fred Miranda wrote:
It looks like the interest for PCX solutions diminish a lot because we have some many native options now.
My interest is greater than ever, because I'm pretty sure a PCX could make certain lenses work on the Fuji GFX. There is a ton of cheap, small, sharp and fast 85 mm lenses that fully covers the 33x44 mm sensor, but almost all of them give the same dreaded backwards curvature of field that we're familiar to with M lenses on Sony. Which isn't strange since the GFX sensor stack is even thicker and the sensor larger.
I'd kill to make my ZF 50/1.4 work properly at 33x38 mm or so. Now it's sort of usable at 33x33 if you stop down a tad. But still more curvature than on a Sony. The image circle is larger than that, though.
Before I go down the route of trying to order all of the items needed for a PCX for a Ultron 35 1.7 does anyone happen to have one they're not using anymore that they'd want to sell?
Postlm wrote:
Haruhiko*T and all the other thread contributors, thank you for sharing precious information that I could not find anywhere else. I'll order PCX.
Do let us know which camera & lens & PCX you are planning to adapt and share feedback.
I finally got an Optsigma plano-convex lens. It took 3 months.
I'm more than happy with my 7Rii (Kolari Original Thin Mod, not UT) + Contax G28 + Optsigma 2500.
Surprisingly sharp from corner to corner which was not possible without Optsigma lens.
I find B+W NL-1 75844 filter is perfect to attach Optisigma lens. Lens is still slightly smaller than the ring, so I attached gaffer tape around it.
I use autofocus adapter which works pretty well, but not 100% time. I like it, and will keep using it.
Thank you guys for the valuable information, this is by far the best camera + lens I have owned.
Postlm wrote:
I finally got an Optsigma plano-convex lens. It took 3 months.
I'm more than happy with my 7Rii (Kolari Original Thin Mod, not UT) + Contax G28 + Optsigma 2500.
Surprisingly sharp from corner to corner which was not possible without Optsigma lens.
I find B+W NL-1 75844 filter is perfect to attach Optisigma lens. Lens is still slightly smaller than the ring, so I attached gaffer tape around it.
I use autofocus adapter which works pretty well, but not 100% time. I like it, and will keep using it.
Thank you guys for the valuable information, this is by far the best camera + lens I have owned....Show more →
Heartiest congratulations and appreciate your patience- 3 months of wait in today’s Covid situation is definitely not easy.
Make sure your PCX is centered if using tape(I use a blackened wide rubber band for the spacing & centering). Did you try mounting a polariser or ND filter & check vignette?
Do share images taken with your 28g. Curious to also see 21g results with your setup(in case you have this WA lens).
I find lower left corner may be very slightly softer than the other corners. I don't know if its lens or the filter centering, but I'll try rubber band. Good idea indeed.
I don't have 21mm unfortunately. Actually I don't have any other lenses. I only have Contax T3 other than this camera. I sold all unused cameras last few years including Mamiya 7ii (I miss it a little...) to minimize my setup.
I find lower left corner may be very slightly softer than the other corners. I don't know if its lens or the filter centering, but I'll try rubber band. Good idea indeed.
I don't have 21mm unfortunately. Actually I don't have any other lenses. I only have Contax T3 other than this camera. I sold all unused cameras last few years including Mamiya 7ii (I miss it a little...) to minimize my setup.
Do share images.
You could use a black velvet tape/sticker/band as well if you find one- I had this initially; worked good with centering and also reflections but keeps slipping out if you keep mounting/unmounting between lenses. The rubber band still hadn’t moved.
BTW- I got my 4 CG lenses as well as the tiny Contax G1 original leather bag from Japan for a bargain. Today I am happy with all 4 lenses and the Nikon z6 in this small bag together
I have no knowledge of front end filters, so I have a question, can any of the ZM lenses be used for landscape where its not necessary to add a front filter.
From the brief reading I have done in this thread, it appears ones uses those filters if they want to use the lens wide open.
A comment was made from 5.6 on you really don't need the front end filter.
IndyFab wrote:
I have no knowledge of front end filters, so I have a question, can any of the ZM lenses be used for landscape where its not necessary to add a front filter.
From the brief reading I have done in this thread, it appears ones uses those filters if they want to use the lens wide open.
A comment was made from 5.6 on you really don't need the front end filter.
I have not tested the ZM lenses per se but you could search the forums here for good examples. The Contax g Wide Angle lenses show significant improvement using a correct PCX even at f5.6 and higher. For landscape where all round sharpness would definitely matter, the PCX becomes indispensable.
I have only two ZM lenses. The 85mm f/4 is perfectly usable wide open for landscapes, although it is at it's best for me when closed down a bit. I enjoy using my ZM 35/1.4 for landscapes, generally closed down to about f/7.1 if I want sharp corners in the 2x3 format, usually focused at midframe or focused as illustrated in the section titled "Achieving optimal focus at infinity with rangefinder wide angle lenses" in this review to account for the field curvature induced by the Sony filter stack:
(Like the author of that review, I often simply set the lens focus at the left end of the infinity mark.)
At wider apertures, though, I tend to either avoid caring about the corners or to crop the images so the resulting corners are just fine--and the rest of the field really sparkles. My tape-currency-to-my-bathroom-mirror-and-focus-at-40-times-focal-length test suggests I can be content with the cropped corners at the largest size that I print (16x20 inches) at f/4 and smaller apertures. Moreover, treating the 36mm-ish ZM as an almost 40mm lens by cropping the 42mp image to 4,800 x 6,000 pixels does still more to avoid corner sharpness issues yet still gives me my largest prints at 300 ppi and across the frame image quality that suits me--so long as corner sharpness at wider apertures isn't a priority.
BrandonSi wrote:
Before I go down the route of trying to order all of the items needed for a PCX for a Ultron 35 1.7 does anyone happen to have one they're not using anymore that they'd want to sell?
Hi, sent you a PM
And for anyone possibly interested, I have an Optosigma 5000PM already mounted that I was using with my 35 ZM that I'm selling, since I begrudgingly sold the lens some time ago.
