p.3 #1 · Voigtlander Ultron 28mm f/2 Lens tests with PCX Front Filter
retrofocus wrote:
Simple question: what is with the old rule that adding glass always leads to some debit (not going into the UV glass discussion here)? Or in another way: even if this glass improves on the corners somewhat, what is the debit by adding glass on an otherwise already optimized lens?
I wondered this exact same thing. I never use a "protective" filter (except ND and CPL) and probably never will. I read on a respectable blog that there is a yearly decline (past 5yrs) of people even bothering to use a filter anymore. It will indeed degrade image quality (very, very, very minimal though) but the reflections are my main reason. Even with the best filters, there is a penalty. I think with PCX filters, the benefits of the corrections far outweigh having another glass layer in the optical path. BUT - never discuss politics or filters on a photo forum....
p.3 #2 · Voigtlander Ultron 28mm f/2 Lens tests with PCX Front Filter
Gary Clennan wrote:
I wondered this exact same thing. I never use a "protective" filter (except ND and CPL) and probably never will. I read on a respectable blog that there is a yearly decline (past 5yrs) of people even bothering to use a filter anymore. It will indeed degrade image quality (very, very, very minimal though) but the reflections are my main reason. Even with the best filters, there is a penalty. I think with PCX filters, the benefits of the corrections far outweigh having another glass layer in the optical path. BUT - never discuss politics or filters on a photo forum.... ...Show more →
I agree. I never use UV filters but in this case it's worth it.
The PCX corrects the induced field curvature/astigmatism and also acts as a protection filter as well.
p.3 #3 · Voigtlander Ultron 28mm f/2 Lens tests with PCX Front Filter
Well these are 95 dollars so not your average UV filter glass . Basically these are optical elements that they would use in lenses. Now you can buy them uncoated for less but we have been using coated ones. I have yet to see any degradation. Actually on center if anything I’m seeing a tiny bit of improvement. But unless I am shooting a real test resolution chart than I can’t confirm it. I’m not going to shoot charts sorry that’s not for me. Lol
If there is degrading in the mid frame or corners the Benifits are certainly hiding it
Btw I have not used a actual UV filter in maybe 20 years or longer on a regular basis. I have used them on jobs where I know the lens could be in danger though. Flying debris stuff
p.3 #4 · Voigtlander Ultron 28mm f/2 Lens tests with PCX Front Filter
retrofocus wrote:
As I said in my response to Guy above, I don't think this kind of filters are needed at all with this lens when mounted on a Sony camera - at least telling from performance on my A7R. The last two photos in my post above were taken with the Sony A7R and this lens (with Fotasy M/E-mount adapter).
@retrofocus,
I run some tests today and actually agree with you that a PCX front-lens may not be crucial for this lens. Some lenses benefit tremendously from adding a PCX front-lens but in the case of the CV 28/2 Ultron, I would not consider it mandatory for the Sony sensor stack. I am getting very sharp corners starting at f/6.7 without the front-lens. Perhaps the design of this lens allows for that to happen just like the CV 15/4.5III.
I'm not saying the optimum PCX won't make the lens even better though. Perhaps it will look great from center to corners at a much wider aperture like f/4. I will check that tomorrow when I get the PCX for it.
So, for those who don't want to use a PCX, the CV 28/2.8 is really great center to corner starting at f/6.7 and that's pixel peeping to the extreme corners! Not that far behind at f/5.6.
What I found was some RSA with this lens. (Residual spherical aberration)
So, there is strong focus shift and we should focus it at shooting aperture for best results.
p.3 #5 · Voigtlander Ultron 28mm f/2 Lens tests with PCX Front Filter
Have you guys thought about getting thinner adapters made? It seems like there's a large enough contingent of you that making a batch purchase could be reasonable.
p.3 #6 · Voigtlander Ultron 28mm f/2 Lens tests with PCX Front Filter
Which is not what I did on the Big Bronco test I loaded up this morning. I spotted it when I was doing the center posts about a hour later I went back and looked and 2.8 was soft as I focused at F2 and F4 was soft. Fred confirmed it later in the day on his tests that he spotted it. So going forward I will focus at working aperture. So I will do it again without the PCX and with once I get the correct strength Friday. Given that this lens is damn good without but the focus shift did not show its strength. So will see now how things shape up. I’m in agreement with Fred we will most likely get to F4 with it on. So I’m all over that
p.3 #7 · Voigtlander Ultron 28mm f/2 Lens tests with PCX Front Filter
freaklikeme wrote:
Have you guys thought about getting thinner adapters made? It seems like there's a large enough contingent of you that making a batch purchase could be reasonable.
I still like to see if the Hawks or VC could possible be adjusted somehow. The other thing is the adapters are cheap at 20 dollars I bought three and two work. So not a big deal per say. But yes be nice if we could have custom ones made for commercial use or a close focus adapter like a Hawks made to our specs.
We need someone that knows these mechanical adapters to tear down and see what can be done
p.3 #9 · Voigtlander Ultron 28mm f/2 Lens tests with PCX Front Filter
Once your. There search SLB-50-2500pm
Zoom
These are simple lenses having a flat surface on one side and a spherical surface on the other. They are also very close to the form which minimizes spherical aberration for infinite conjugate applications. Our glass lenses are made from the highest grade of optical glass. We have a vast range of different diameters and focal lengths. The lenses listed here are standards. Please call if you do not see the lens you need. We have both larger and smaller lenses and many other diameters to choose from. However, we do try to keep these standards available for quick delivery.
◦There are three types of plano convex lenses available; BK7 for use in visible range to infrared wavelength range.
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Outline Drawing
p.3 #10 · Voigtlander Ultron 28mm f/2 Lens tests with PCX Front Filter
freaklikeme wrote:
Have you guys thought about getting thinner adapters made? It seems like there's a large enough contingent of you that making a batch purchase could be reasonable.
from my recent CNC orders, i'd estimate you could get full adapters (no helicoid) made for $100 each in a batch of 5 or thinner adapter inserts for $70 each in a batch of 5. obviously cheaper if you want to get 20 or 100 made...
doesn't seem worth it when thin adapters are easily available for ~$12, but getting a thinner version of the mounting part of the hawk's adapter might be worthwhile.
I noticed yesterday that the direct links to the site work when they are copy-pasted to browser from here but don't work when double-clicking on the links here (they end up at higher level and don't reach the page for the right item, so it seems some of the parameters get converted to something wrongly, perhaps due to special characters in the URLs)... At least that's how it is on my PC.
p.3 #12 · Voigtlander Ultron 28mm f/2 Lens tests with PCX Front Filter
Yea for some reason the link does not take you directly to the page. Just do a search on the model number on their site and you can read more about these filters we are using. Nice folks BTW
p.3 #13 · Voigtlander Ultron 28mm f/2 Lens tests with PCX Front Filter
sebboh wrote:
from my recent CNC orders, i'd estimate you could get full adapters (no helicoid) made for $100 each in a batch of 5 or thinner adapter inserts for $70 each in a batch of 5. obviously cheaper if you want to get 20 or 100 made...
doesn't seem worth it when thin adapters are easily available for ~$12, but getting a thinner version of the mounting part of the hawk's adapter might be worthwhile.
Does anyone have connections to Hawks? Bastian tried some time ago to talk with their support but to no avail.
p.3 #14 · Voigtlander Ultron 28mm f/2 Lens tests with PCX Front Filter
GMPhotography wrote:
Yea for some reason the link does not take you directly to the page. Just do a search on the model number on their site and you can read more about these filters we are using. Nice folks BTW
I found that copying the link from here by copy-paste to Browser's web-address field does the thing easiest Yesterday I tried to search for the PCX for the 35mm lens first with various searches on the site but it didn't work out that easily.
p.3 #15 · Voigtlander Ultron 28mm f/2 Lens tests with PCX Front Filter
sebboh wrote:
from my recent CNC orders, i'd estimate you could get full adapters (no helicoid) made for $100 each in a batch of 5 or thinner adapter inserts for $70 each in a batch of 5. obviously cheaper if you want to get 20 or 100 made...
doesn't seem worth it when thin adapters are easily available for ~$12, but getting a thinner version of the mounting part of the hawk's adapter might be worthwhile.
I guess it depends. I couldn't get one thin enough for the Elmarit 24, and my efforts to tinker with the helicoid stops resulted in a small disaster. I eventually managed to piece it back together and get it centered without having to send it off. Great learning experience, but I'd happily pay $100 not to repeat it.
You and Guy are right, though. A helicoid would be right way to go, since you have to vary the distance by lens.
p.3 #16 · Voigtlander Ultron 28mm f/2 Lens tests with PCX Front Filter
sebboh wrote:
from my recent CNC orders, i'd estimate you could get full adapters (no helicoid) made for $100 each in a batch of 5 or thinner adapter inserts for $70 each in a batch of 5. obviously cheaper if you want to get 20 or 100 made...
doesn't seem worth it when thin adapters are easily available for ~$12, but getting a thinner version of the mounting part of the hawk's adapter might be worthwhile.
I also asked Novoflex. Adapter itself is 149€, modifying 300€ on top (for a single unit).
p.3 #18 · Voigtlander Ultron 28mm f/2 Lens tests with PCX Front Filter
300€ for tuning an adapter ?. I modified my Pixco to a thickness of 9.30mm in an hour or so. Working 8 hours I could make 2400€ a day. What I’m waiting for ?
In all truth, adjusting an adapter at home without special tools isn’t the best formula for absolutely parallel and even surfaces. With a lot of patience and a few sheets of grinding paper I managed to achieve a regularity of +-0.02mm. all around the adapter. Probably good enough to practical effects, except for the most demanding pixel peeping, but far from a professional job.
