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Front-End Filter Improves Corner Smearing

  
 
GMPhotography
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p.90 #1 · Front-End Filter Improves Corner Smearing


No I can't remember. Im getting old bud.


Oct 03, 2017 at 11:41 AM
Fred Miranda
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p.90 #2 · Front-End Filter Improves Corner Smearing


Gunzorro wrote:
Ha-ha!

Well, I'm certainly an ignorant one!

Thanks for the reminder, Fred -- about the M-mount, not the ignorance.


On the contrary! It would be great if you could join the FM PCX team!



Oct 03, 2017 at 11:42 AM
Fred Miranda
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p.90 #3 · Front-End Filter Improves Corner Smearing


GMPhotography wrote:
No I can't remember. Im getting old bud.


I remember you sent me some tear down pictures.



Oct 03, 2017 at 11:43 AM
Gary Clennan
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p.90 #4 · Front-End Filter Improves Corner Smearing


Does anyone know which PCX filter(s) would be best suited for a 28cron asph and 50lux asph? No idea where to start.... I'm interested in giving it a whirl.


Oct 03, 2017 at 12:13 PM
GMPhotography
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p.90 #5 · Front-End Filter Improves Corner Smearing


I think I found the Ultron 28 teardown. Thanks Fred


























Edited on Oct 03, 2017 at 12:31 PM · View previous versions



Oct 03, 2017 at 12:19 PM
Fred Miranda
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p.90 #6 · Front-End Filter Improves Corner Smearing


Gary Clennan wrote:
Does anyone know which PCX filter(s) would be best suited for a 28cron asph and 50lux asph? No idea where to start.... I'm interested in giving it a whirl.


For the 50lux you would need a PCX 10m. I'm not sure about the 28cron.







Oct 03, 2017 at 12:19 PM
Gary Clennan
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p.90 #7 · Front-End Filter Improves Corner Smearing


Fred Miranda wrote:
For the 50lux you would need a PCX 10m. I'm not sure about the 28cron.


Thanks Fred! Is there anything I need to look for when ordering? Any preferred vendors?



Oct 03, 2017 at 12:23 PM
Fred Miranda
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p.90 #8 · Front-End Filter Improves Corner Smearing


Gary Clennan wrote:
Thanks Fred! Is there anything I need to look for when ordering? Any preferred vendors?


OptoSigma does not offer a 10m PCX. You may have better luck with Eksma Optics. Make sure to get a coated version.



Oct 03, 2017 at 12:30 PM
sebboh
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p.90 #9 · Front-End Filter Improves Corner Smearing


GMPhotography wrote:
I think I found the Ultron 28 teardown. Thanks Fred


ok, my guess is that infinity adjustment can be done by changing the orientation of the focus ring in relation to the brass part of the helicoid in your second image. not sure how they're attached from the image so it's tough to say how one would do that. often there is a set screw (or two or three) that can't be easily accessed without removing the focus ring from that brass portion of the helicoid.



Oct 03, 2017 at 01:39 PM
hanay78
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p.90 #10 · Front-End Filter Improves Corner Smearing


Hello, thank you for this post. I have read in other threads that techart adapter was able to focus at infinit with the contax g 21 ... It looks there is some contradictory information or most probably I am missing something. I am sorry I am just a newby best regards and thank you in advance for your help.


Oct 03, 2017 at 02:15 PM
 


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sebboh
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p.90 #11 · Front-End Filter Improves Corner Smearing


hanay78 wrote:
Hello, thank you for this post. I have read in other threads that techart adapter was able to focus at infinit with the contax g 21 ... It looks there is some contradictory information or most probably I am missing something. I am sorry I am just a newby best regards and thank you in advance for your help.


i'm pretty sure the OP got that to work fine. most of these posts about reaching infinity are regarding voigtlander lenses on the m-mount techart adapter, not contax g lenses on contax g mount techart (though i've heard some people having issues with some adapters on the contax g 28).



Oct 03, 2017 at 02:33 PM
Fred Miranda
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p.90 #12 · Front-End Filter Improves Corner Smearing


Got the Ultron 28/2 today.
With the 5m PCX and my 'short' K&F Concept adapter, infinity is at the 5m mark, so I think I have a lot of room for a stronger PCX front-lens. I will take some pictures of the lens (front and rear ) and send it in for simulation today.
Fred



Oct 04, 2017 at 02:36 PM
Fred Miranda
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p.90 #13 · Front-End Filter Improves Corner Smearing


BTW: At f/6.7 (these Ultrons go half stops), the image is already very sharp to the very corners with the "5m" front lens. Which probably is not the optimal PCX for it.

Here is a crop showing the extreme edges. Mid-field and center look great as well. (but not as good as CV 35/1.7)

I'm actually surprised the extreme corners look that good with the 5m PCX. Perhaps the optimal will be around 3m.












Oct 04, 2017 at 02:44 PM
GMPhotography
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p.90 #14 · Front-End Filter Improves Corner Smearing


Does look pretty good actually


Oct 04, 2017 at 03:46 PM
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p.90 #15 · Front-End Filter Improves Corner Smearing


GMPhotography wrote:
Does look pretty good actually


I'd say it's actually excellent starting at f/6.7. At infinity, it's already better than the ZF 28/2, ZM 28/2.8 + PCX and I dare to say Leica 28/2.8 R II. All these lenses need f/8 or f/9 for the edges.

There is also the possibility this performance could improve when using the optimal PCX for it.

Center resolution looks great but not as good as the CV 35/1.7 @ f/2. That's probably one of the sharpest 35mm lens I've tested.



Oct 04, 2017 at 10:30 PM
kaioyang
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p.90 #16 · Front-End Filter Improves Corner Smearing


How does it look if un-corrected? Does it ever get sharp at corners?


Oct 04, 2017 at 10:41 PM
genji
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p.90 #17 · Front-End Filter Improves Corner Smearing


kaioyang wrote:
Speaking of 28mm, has anyone tested the Minolta M-rokkor 28/2.8? What filter strength would it need?


Also speaking of 28mm, has anyone tested the Konica M-Hexanon 28/2.8?



Oct 05, 2017 at 12:45 AM
HaruhikoT
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p.90 #18 · Front-End Filter Improves Corner Smearing


Based on Fred's picture of the lens itself I run simulation for CV28 F2.
PCX 2m may be the best and 2.5m also looks very good. From my quick check 1.5m was not good, and 3m is also good but not the best. Attachment direction of PCX will not affect in this case.



Oct 07, 2017 at 03:39 AM
GMPhotography
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p.90 #19 · Front-End Filter Improves Corner Smearing


Thank you.


Oct 07, 2017 at 04:41 AM
nehemiahphoto
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p.90 #20 · Front-End Filter Improves Corner Smearing


Steve Spencer wrote:
Thanks Derek, I always value your opinion and find it quite helpful. I have the ZM 35 f/1.4 and my problem is that I bought it hoping that I could use it in two different kits and it works quite well in one, but not so well in the other. Where it works for me is in a three lens kit with the Sony A7r II and the Loxia 21 and Loxia 85. These three make a nice fairly small versatile kit. At the wide end the Loxia 21 is fantastic at most everything I want it for. The
...Show more

Steve,

I am in the same boat as you--looking for an everything 35. Aside from the Rx1 which obviously isn't interchangeable, I find the Pentax 31 the best. In terms of draw and portraits, to my mind it's only beat by the CY 35. I borrowed mine to Derek, so he might have an updated opinion. But it's lovely WO (though has some LoCa and a pinch of SA-which I welcome), no pcx filter needed, middle size/weight, lower end for price, and excellent sharpness across the frame slightly stopped down. Flare isn't as good as the ZM35 or CV though. It's 32mm. I prefer it over my ZA 35 (which has restricted usage because it's huge). the Pentax 31 has a smooth rich character draw, would couple nicely with the r80.

Tbh, between the cv 35, rx1, zm 35, CY 35 and Pentax 31 the images and rendering are all pretty excellent, just a matter of what you want to deal with (filters, mf feel, bokeh, price, weight)

Also, all you guys excited to restart all this crazy testing once canon and nikon release FF mirrorless cams with differ sensor stacks? 🤣











































Oct 07, 2017 at 05:34 AM
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