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Archive 2016Front-End Filter Improves Corner Smearing

  
 
Fred Miranda
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p.54 #1Front-End Filter Improves Corner Smearing
last one...extreme edges at f/4. (see below)

BTW: I used a mid-zone closer to the edge because it seemed to be where the issue was based on the images posted here.

Also, just to confirm adding a blank 49mm before the filter set-up (to be able to use the OEM hood) does not affect IQ at all. The images look identical (with the extra blank 49mm filter or without). I thought could slightly degrade resolution since the front-lens would be positioned further from the ZM lens but there is no issue at all.

It's worth mentioning that images with the front-lens look better even at f/8 when compared to bare lens. The difference is much smaller but still noticeable at 1:1. In my opinion, the PCX 5m is a non-brainier for the ZM 35/1.4.





f/4 (extreme edge)







full image thumbnail

Feb 25, 2017 at 04:03 PM
Makten
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p.54 #2Front-End Filter Improves Corner Smearing
Fred Miranda wrote:
For those who do not care about using the OEM hood or additional filters, a simple 49-55, 55-52 + 52 retention ring will do the trick.


Why the 49-55 + 55-52 instead of 49-52?
Feb 25, 2017 at 04:27 PM
Fred Miranda
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p.54 #3Front-End Filter Improves Corner Smearing
Makten wrote:
Fred Miranda wroteFor those who do not care about using the OEM hood or additional filters, a simple 49-55, 55-52 + 52 retention ring will do the trick.
Why the 49-55 + 55-52 instead of 49-52?


Do you mean just adding a 49-52 with a 52 retaining ring?
That won't work because the PCX lens is too thick.

You could do 49-52 + blank 52 + retaining ring. That's also an alternative I tried that works. However, it will be more prone to vignetting. (and looks longer)
Feb 25, 2017 at 04:30 PM
Luvwine
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p.54 #4Front-End Filter Improves Corner Smearing
For someone who whose technical skills are not much beyond screwing on a filter, is this modification sensible to try? Is there a way to do it without special tools and know how? I am specifically referring to the ZM 35. Happy to buy the components, just a bit unclear on assembly. Thx!
Feb 25, 2017 at 04:40 PM
GMPhotography
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p.54 #5Front-End Filter Improves Corner Smearing
Really just need a spanner wrench. Like 15 dollars on amazon
Feb 25, 2017 at 04:42 PM
Makten
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p.54 #6Front-End Filter Improves Corner Smearing
Fred Miranda wrote:
Do you mean just adding a 49-52 with a 52 retaining ring?
That won't work because the PCX lens is too thick.

You could do 49-52 + blank 52 + retaining ring. That's also an alternative I tried that works. However, it will be more prone to vignetting. (and looks longer)


I really don't understand the difference. How could a longer stack of rings give less vignetting?

Edit: I'd like to know how the heck the filter is held in place and why you have to have so many of those rings. Doesn't make sense.
Perhaps someone could make a sketch/drawing of it all?
Feb 25, 2017 at 04:44 PM
GMPhotography
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p.54 #7Front-End Filter Improves Corner Smearing
A 52mm is a narrower angle of view plus with a retaining ring it's even narrower. Believe me I tired this several ways and if you want to keep the hood in place what Fred and I did is simply the best solution. This comes at some pretty good expense of trying different ways. The EL Pro retaining ring is the key since you don't have to add a step down from 55-52 just stay at 55 with the ring which retains it perfectly it also shortens the length. Sounds crazy but it works.

Also testing at F8 is mandatory for vignettng as that is the most accurate aperture
Feb 25, 2017 at 04:53 PM
GMPhotography
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p.54 #8Front-End Filter Improves Corner Smearing
Remember also because of the hood we have to have a 49mm slim filter ring to get past the hood mount. If not using the hood you don't need it to start the set.
Feb 25, 2017 at 04:56 PM
Chuck Coyne
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p.54 #9Front-End Filter Improves Corner Smearing
Fred/Guy

I've received the Leica ELPro 3 lens I ordered from eBay, the Tiffen 49 UV filter and Sensei Pro 49-55mm step up ring + 55mm Tiffen UV filter arrive Monday. I ordered the SLB 50-5000PM pcx filter from OptoSigma (4-5 week estimated delivery hopefully sooner).

I'd like to get everything setup so when the pcx lens arrives I'm ready to go.

Can you describe how you get the thick glass lens out of the ELPro 3 ring? You mention a spanner wrench. How do you use that to get to a 55mm retainer ring? maybe I'm missing something, can't you just break the glass lens and pull the broken glass out of the ELPro 3 ring? I assume you can just break the UV filter glass and pull the pieces out of the Tiffen UV filters to get the blank rings?

Sorry if there is somewhere else that describes this process but I searched and couldn't find a detailed description.

Thanks,

Chuck

Feb 25, 2017 at 05:09 PM
GMPhotography
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p.54 #10Front-End Filter Improves Corner Smearing
The retaining ring is in the very front it should have 2 slots in it but Fred got one without. He drilled a hole in the retaining ring to push it to rotate. But you could just break the dang glass to free up the ring so you can just use your fingers if you don't have the slots. Can you post a shot of the inside front side . We can guide you from there
Feb 25, 2017 at 05:13 PM
Chuck Coyne
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p.54 #11Front-End Filter Improves Corner Smearing
Guy,

Thanks, I left the ELPro 3 at my office so I'll take a shot of it tomorrow. But basically you have to unscrew the retaining ring from the front of the ELPro 3 to use it to secure the pcx lens into the step up ring? I think I got it now thanks!

Edited on Feb 25, 2017 at 08:21 PM · View previous versions
Feb 25, 2017 at 05:21 PM
tormoder
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p.54 #12Front-End Filter Improves Corner Smearing
I have lately done two attempts to test the G45 with the SLB-50-5000PM filter:

https://tormoder.no/photo/g45-5m-pcx-1/
https://tormoder.no/photo/g45-5m-pcx-2/

I have not studied the results too closely yet. There seems to maybe be a very
small corner improvement from f/2 to approximately f/5.6, but it is nothing
spectacular as opposed to the G21/G28. Any comments are welcome.

I think this filter most likely will be permanent on my VC35 instead.
Feb 25, 2017 at 05:28 PM
GMPhotography
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p.54 #13Front-End Filter Improves Corner Smearing

Yes
Chuck Coyne wrote:
Guy,

Thanks, I'll left the ELPro 3 at my office so I'll take a shot of it tomorrow. But basically you have to unscrew the retaining ring from the front of the ELPro 3 to use it to secure the pcx lens into the step up ring? I think I got it now thanks!

Feb 25, 2017 at 06:09 PM
Fred Miranda
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p.54 #14Front-End Filter Improves Corner Smearing
Makten wrote:
Fred Miranda wroteDo you mean just adding a 49-52 with a 52 retaining ring?
That won't work because the PCX lens is too thick.

You could do 49-52 + blank 52 + retaining ring. That's also an alternative I tried that works. However, it will be more prone to vignetting. (and looks longer)
I really don't understand the difference. How could a longer stack of rings give less vignetting?

Edit: I'd like to know how the heck the filter is held in place and why you have to have so many of those rings. Doesn't make sense.
Perhaps someone could make a sketch/drawing of it all?


The longer the filter set-up and the smaller the resulting filter thread, the more likely you will see vignetting.

Basically we have 3 options for the ZM 35/1.4.

1) 49-55 + 55-52 + 52 retaining ring
2) 49-52 + Blank 52 + 52 retaining ring
3) 49-55 + Blank 55 + 55 retaining ring

Notes:
Number 1) is a great solution. it's the one that @HaruhikoT posted here:
https://www.fredmiranda.com/forum/topic/1453834/12#13842683

Number 2) is an alternative solution but it's a bit longer and therefore may vignette more depending on the thickness of your filters.

3) IMO, it's the best solution as far vignetting goes but it will require a special (thicker) 55mm retaining ring. (The one found on the Leica ELPRO 3 or ELPRO 4 close-up filters)

Number 1) and 3) do not vignette by themselves but only 3) can be used with the original OEM hood and additional filters without introducing vignetting.

PS: To use 3) with the original OEM hood we must start with a blank 49mm slim filter so that when the hood is in place, there will be threads to attached to the filter set-up.

See final result picture here:
https://www.fredmiranda.com/forum/topic/1453834/52#13935599
Feb 25, 2017 at 06:19 PM
HaruhikoT
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p.54 #15Front-End Filter Improves Corner Smearing
tormoder wrote:
I have lately done two attempts to test the G45 with the SLB-50-5000PM filter:

https://tormoder.no/photo/g45-5m-pcx-1/
https://tormoder.no/photo/g45-5m-pcx-2/

I have not studied the results too closely yet. There seems to maybe be a very
small corner improvement from f/2 to approximately f/5.6, but it is nothing
spectacular as opposed to the G21/G28. Any comments are welcome.

I think this filter most likely will be permanent on my VC35 instead.


This is the first G45+PCX real field test as far as I know! Thank you so much.

In your comparison 1, I can see contrast improvement in 'Midzone 2' and 'Extreme corner' @F2.
And in comparison 2, branches in 'Right side' look clearly sharper with PCX from F2 to F5.6.

G45's corner looks much less problematic than G21/28 even without PCX.
Also, G45's designed MTF is not so best on its extreme corner, although this was one of the sharpest lenses in the film era. This PCX method can't improve aberrations which master lenses originally have.
That's because the results are not so spectacular, I think.
Feb 25, 2017 at 08:18 PM
HaruhikoT
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p.54 #16Front-End Filter Improves Corner Smearing
BastianK wrote:
Thanks for sharing @HaruhikoT@@!

Interestingly the results from your copy are almost indistinguishable from the ones I get.
On my lens lower left looks significantly better than upper right as well.
Makes me frighten how similar it actually looks...
I also assumed a perfectly centered lens may not show the significant mid zone dip,
in case @Fred Miranda@@ has a golden copy this would explain why he didn't notice it.

I found this decentering to also be apparent without filter so I send the lens in, but my hopes are not too high,
I am actually already prepared for some nonsense "within tolerances" talk.
Will have to send
...Show more →
HaruhikoT wroteHi @BastianK@@ and @Phillip Reeve@@,

I've just uploaded raw files of ZM35/1.4 + Opto 5m shots at F1.4 & infinity.
https://drive.google.com/drive/folders/0B1BhTESBmBxoVXVNS3lGNWNuRW8

Your mentioned "midzone dip" also appears in my copy.
Compared to the center, sharpness goes lower in the area 50-80% off center, then around 90% off center, it goes higher again.
And I also see upper-right midzone is slightly worse than lower-left midzone.
I'd carefully checked my filter centering using @scrappydog@@'s method, so perhaps my ZM35 is not a best copy...

But I have to say, even in the midzone, sharpness seems to be not worse than without PCX.
And as Guy mentioned, I also see midzone goes best at F4 or higher, whereas it is not that good without PCX below F8.

In my conclusion, there is no doubt PCX 5m improves ZM35/1.4's overall sharpness, but still have a little weakness at wider aperture.


I'm also considering to send mine to Cosina Japan(where I believe it was actually made) for inspection, but not immediately, because I need to use this lens almost every weekend
If you get good response or good fixed centering copy from Zeiss, please let me know!
Feb 25, 2017 at 09:10 PM
robgo2
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p.54 #17Front-End Filter Improves Corner Smearing
I just tested the CV Ultron 35/1.7 with the same front end setup that I use on my ZM 35, except that I start with a 46-55 stepup ring. Unfortunately, I cannot reach infinity focus with the Hawk adapter. Does anyone know if it is possible to remove shims from the Ultron?

Rob
Feb 26, 2017 at 11:28 AM
GMPhotography
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p.54 #18Front-End Filter Improves Corner Smearing

Not sure but I would start at the lens mount itself and just see if it's in the mount
robgo2 wrote:
I just tested the CV Ultron 35/1.7 with the same front end setup that I use on my ZM 35, except that I start with a 46-55 stepup ring. Unfortunately, I cannot reach infinity focus with the Hawk adapter. Does anyone know if it is possible to remove shims from the Ultron?

Rob

Feb 26, 2017 at 11:49 AM
mcbroomf
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p.54 #19Front-End Filter Improves Corner Smearing
robgo2 wrote:
I just tested the CV Ultron 35/1.7 with the same front end setup that I use on my ZM 35, except that I start with a 46-55 stepup ring. Unfortunately, I cannot reach infinity focus with the Hawk adapter. Does anyone know if it is possible to remove shims from the Ultron?

Rob


I removed the 4 rear screws (flat) and pulled off the silver ring (mount). Underneath there are no shims, just another black ring with 3 cross head screws. I took them off and pulled off the black ring. Also no shims, the rear of the helicoid is exposed. Not having any kind of lens experience I left well alone and put it back together. The flat screws were tough to get moving as they had some threadlock in them, so be careful if you try this.

Mike

Feb 26, 2017 at 12:10 PM
robgo2
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p.54 #20Front-End Filter Improves Corner Smearing
mcbroomf wrote:
robgo2 wroteI just tested the CV Ultron 35/1.7 with the same front end setup that I use on my ZM 35, except that I start with a 46-55 stepup ring. Unfortunately, I cannot reach infinity focus with the Hawk adapter. Does anyone know if it is possible to remove shims from the Ultron?

Rob
I removed the 4 rear screws (flat) and pulled off the silver ring (mount). Underneath there are no shims, just another black ring with 3 cross head screws. I took them off and pulled off the black ring. Also no shims, the rear of the helicoid is exposed. Not having any kind of lens experience I left well alone and put it back together. The flat screws were tough to get moving as they had some threadlock in them, so be careful if you try this.

Mike



Mike, you have just convinced me not to mess with that lens. I think that Bastian has used a particular adapter that was able to reach infinity focus, but I don't remember which one--either Fotasy or Fotodiox.

Rob



Feb 26, 2017 at 04:28 PM
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