Thanks @BastianK !
This makes the job very easy for those willing to adjust the ZM 35/1.4 by just keeping the 'gold' shim under the bayonet. What was the resulting infinity focus position on the lens ring without the filter on?
I didn't know there were shims under the bayonet as well. That may be the case for the ZM 28/2.8 as well.
Fred Miranda wrote:
Thanks @BastianK@ !
This makes the job very easy for those willing to adjust the ZM 35/1.4 by just keeping the 'gold' shim under the bayonet. What was the resulting infinity focus position on the lens ring without the filter on?
I just checked, pretty exactly 5 meters.
Of course I don't know if any copy of this lens has the same exact shim setup,
I would think there might be some sample variation here.
Furthermore there are of course slight differences in adapter thickness,
so in case you are not using the VM-E close focus you might come to a different conclusion.
But for me removing shims and being able to keep using the lens with a helicoid adapter
is definetly the way better solution compared to a shorter (non helicoid) adapter.
As a bonus I now have a perfectly calibrated hard infinity focus stop (didn't before), which is something I really like.
candreyo wrote:
Bastian,
Have you noticed an improvement with field curvature while using the Eksma 5m on the 35mm Distagon ZM?
I'm very tempted to get the OptoSigma 5m lens at this point 😀
May I ask, how much did Laser2000 charge for the lens in Germany?
I had to pay 86.00 GBP (which included VAT and shipping) for the 1500mm Planoconvex from Laser2000 UK.
I wonder if there is another supplier elsewhere in the world that has the 5m OptoSigma lenses in stock?
Field curvature is improved, but with the Eksma 5m there is a significant midzone dip.
You might want to have a look at this post https://www.fredmiranda.com/forum/topic/1453834/20#13856720
The Eksma filter (uncoated, for coating add 67€ and 5 weeks) cost me 83,5€,
the Optosigma filter (coated, estimated delivery in February) cost me 119€ (both with shipping and taxes).
As I see things, the distributors of Optosigma filters rarely have anything in stock
and need to order everything directly from Japan.
From the shots Haruhiko posted it seems the Optosigma filter does not show that significant midzone dip,
so the Eksma filter is more of an interim solution for me until the Optosigma filter arrives.
Therefore at the moment I would not recommend buying the 5m filter from Eksma for the 35mm 1.4.
Wow, the ZM 28/2.8 really looks good on the A7rii with filter - thanks for posting Fred!
Do you guys think the lens could benefit from a filter on the Leica M9 as well?
If so, what filter should that be??
And many thanks Candreyo for the tip about the different shims and focus on a rangefinder - very important! Did you post another video about how to remove the shims?
I have a Leica M240, and what I have noticed is when I put the optimal correction lens for the Sony filter stack on say the ZM28mm lens, it throws off the corners on my M240.
It would seem that the correction needed for the Sony Sensors is different then Leica, which makes sense as we know the Leica sensors have different cover glass thickness and use micro lenses also.
There may be correction lenses that would improve performance on a Leica sensor, but I don't know what those are. Most of my rangefinder lenses work very well with my M240 already, so I've not had a desire to expiirement with what lenses may increase performance.
With that said, it's entirely possible that correction lenses like postive and negative meniscus and Planoconvex could be used to address astigmatism issues on practically any lens and sensor stack combo.
What we have learned here on this forum thread is very new and radical stuff! Many people would not want to place any additional lens in the optic path to try and improve performance, yet that is exactly what some of us tried here, and the results speak for themselves 😀
ceder wrote:
Wow, the ZM 28/2.8 really looks good on the A7rii with filter - thanks for posting Fred!
Do you guys think the lens could benefit from a filter on the Leica M9 as well?
If so, what filter should that be??
And many thanks Candreyo for the tip about the different shims and focus on a rangefinder - very important! Did you post another video about how to remove the shims?
ceder wrote:
Do you guys think the lens could benefit from a filter on the Leica M9 as well?
Even if it would, you'd be in trouble because of the need to recalibrate the rangefinder cam of the lens, in addition to shortening the flange distance.
Fred Miranda wrote:
Thanks @BastianK@ !
This makes the job very easy for those willing to adjust the ZM 35/1.4 by just keeping the 'gold' shim under the bayonet. What was the resulting infinity focus position on the lens ring without the filter on?
I didn't know there were shims under the bayonet as well. That may be the case for the ZM 28/2.8 as well.
Yes, that made me wonder too. Years ago, I replaced the original bayonet of a ZM21/2.8 (in order to get the correct frames in the M8 viewfinder). As far as I recall, there were no shims under the bayonet.
Just a question for Candreyo. Looking at the back of a ZM25, I see two "notched" rings (marked 1 and 2 in the picture below). Which one must be removed for accessing the internal shims ?
I'm guesing it's the outer ring, because the other seems to be holding the rear glass group, but I want to be sure before it's too late ..
It is ring 1, that is the retention ring to hold the lens assembly to the focusing helicoil.
If you unscrew that ring, the front of the lens assembly should pull away from the lower half.
Once you do this, the brass shims can be seen internally.😉
Adjusting the lens this way, leaves the rangefinder focus tab in the same place on the helicoil, which is important for Leica type cameras.
artur5 wrote:
Yes, that made me wonder too. Years ago, I replaced the original bayonet of a ZM21/2.8 (in order to get the correct frames in the M8 viewfinder). As far as I recall, there were no shims under the bayonet.
Just a question for Candreyo. Looking at the back of a ZM25, I see two "notched" rings (marked 1 and 2 in the picture below). Which one must be removed for accessing the internal shims ?
I'm guesing it's the outer ring, because the other seems to be holding the rear glass group, but I want to be sure before it's too late ..
I don't know... maybe I am picky but I just saw a pic from a G21 on a A7RII on another site and I am fairly sure the photog used a front lens for correction but I plainly see a obvious color shift all around the periphery. Definitely not anything close to how this lens performs with color positive film in a Contax G2. On that body it's stellar and near flawless. If I went to the trouble to cut the end and get a front lens and adapters to make it fit to get severe color shift I think I would be far from happy
OK I have been keeping an eye on this thread over the last little while with some interest. I have been able to source a ZM 25 for a ridiculous price however I'm hoping that the experts on this thread might be able to provide me with what I would require for tis specific lens including specific sources for the Plano Convex lens required etc.
Not to worry. We are the pickiest photography group on the planet . If we find issues, it will be reported here.
Jim DE wrote:
I don't know... maybe I am picky but I just saw a pic from a G21 on a A7RII on another site and I am fairly sure the photog used a front lens for correction but I plainly see a obvious color shift all around the periphery. Definitely not anything close to how this lens performs with color positive film in a Contax G2. On that body it's stellar and near flawless. If I went to the trouble to cut the end and get a front lens and adapters to make it fit to get severe color shift I think I would be far from happy...Show more →
ZM 25 is being reported to work well with a Proxar 1m lens.
MIRANDA1 wrote:
OK I have been keeping an eye on this thread over the last little while with some interest. I have been able to source a ZM 25 for a ridiculous price however I'm hoping that the experts on this thread might be able to provide me with what I would require for tis specific lens including specific sources for the Plano Convex lens required etc.
I'm using a 1m Proxar with the ZM 25mm and am getting excellent results.
You can get a Zeiss 1m Proxar in B52 (Hasselblad bayonet mount) off a popular auction website.
From there, you will also need a 46mm to 55mm step up adapter, and a 55mm UV filter that allows the UV lens to be removed via a retention ring.
I then put the step up adapter on the front of the ZM lens, then placed the Proxar lens inside the 55mm diameter opening. I then clamped it in place with the housing for a 55mm UV filter, with the UV lens removed of course.
The 1m Proxar B52 filters I've seen come in a chrome mount. The lens needs to be removed from this mount, I used a rotary cutter on a dremel to carefully cut off the B52 housing to free the lens inside.
There may exist 1m Proxar lenses in black B52 housings? These housing have a retention ring in the rear that can be unscrewed, allowing the Proxar lens to come out.
After putting on the 1m Proxar with adaptor attachments onto the ZM 25mm lens, you will need to adjust the lens now to reach infinity. How to do this has been discussed at length in this thread, however, if you need any help on this, just message me or post here, and I'll help guide you through it 😉
Equally a 1000mm Planoconvex lens may work just as good, but I don't have that type of lens on hand, so can not test this.
OptoSigma sells the Planoconvex lenses in 50mm diameter, multicoated. This setup would need a slightly different mounting arrangement, as the Proxars are 52mm diameter. Fred Miranda wrote:
ZM 25 is being reported to work well with a Proxar 1m lens.
Jim DE wrote:
I don't know... maybe I am picky but I just saw a pic from a G21 on a A7RII on another site and I am fairly sure the photog used a front lens for correction but I plainly see a obvious color shift all around the periphery. Definitely not anything close to how this lens performs with color positive film in a Contax G2. On that body it's stellar and near flawless. If I went to the trouble to cut the end and get a front lens and adapters to make it fit to get severe color shift I think I would be far from happy...Show more →
The colour shift is not affected by the front filter (or indeed the filter stack on the sensor)
It's determined by the well depth and the micro lens angle on the sensor, so it's camera dependent.
RF lenses tend to work best in terns of colour shift on the A7rII, but often have obvious shift on other A7 series bodies.
Even for FM Alt, this thread is insane. I thought swapping the mount (Leitax) to attach lenses to bodies was extreme, but now optical trains are being rejiggered and lenses (re)shimmed. I anticipate being able to enjoy my lovely Elmarit-M 28 ASPH with sharp edges at last!
DavidBM, I noticed the pic in question was also posted on this forum and I was mistaken it was not taken with the a7r2 but with the a7s instead. But color shift on that pic is very obvious.
Fred have you tried the 21G with a this front lens technique on a a7r2? Did you have clearance between the uncut tail of the lens to the camera sensor? Did you see color shift?
I really would love to use my 21G on a digital and get the results I do with it with color film..... If you guys say there is no clearance issues or color shift I will definitely give it a go.
Jim DE wrote:
DavidBM, I noticed the pic in question was also posted on this forum and I was mistaken it was not taken with the a7r2 but with the a7s instead. But color shift on that pic is very obvious.
Fred have you tried the 21G with a this front lens technique on a a7r2? Did you have clearance between the uncut tail of the lens to the camera sensor? Did you see color shift?
I really would love to use my 21G on a digital and get the results I do with it with color film..... If you guys say there is no clearance issues or color shift I will definitely give it a go....Show more →
I have not tried the 21G but I'm pretty sure there will be no color shift on the A7RII. (Only the previous A7 series)
I've not seen any colour shifting on any of my wide angle ZM lenses (18, 25, 28, 35) on the Sony A7Rii.
When I had the A7R (original), I had colour shifting on quite a few lenses.
I thought swapping the mount (Leitax) to attach lenses to bodies was extreme, but now optical trains are being rejiggered and lenses (re)shimmed. I anticipate being able to enjoy my lovely Elmarit-M 28 ASPH with sharp edges at last!