robgo2 wrote:
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
Correct, it was this one, but for another reader it didn't work so there also seems to be some sample variation among adapters
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.
I would like to add a fourth option to Fred's list - a local optometrist quickly and cheaply (NZ$35) edge ground the Optosigma filter down from its original 50 mm diameter to c. 46 mm on his glazing machine, custom fitting it to the rebate in the cheap 49 mm filter I bought and disassembled. He was initially concerned that the glass might be toughened, but an email to AusOptics brought a swift confirmation that this was not the case. The lens coating has survived the process in good shape.
Once I got it home, I initially held it in place with the original retaining ring. This worked okay, but left too little thread for a second filter, so I now have it held in place with a 49-52mm stepup ring, which has the added advantage of allowing me to use 52 mm filters in common with my Loxias.
navmanz, you are a step ahead of me. 😏 I have my pcx 1.5m, 5m and proxar +1 edge grounded today. Thanks for your report, I had more confidence doing that. Slight edge cracked on the 5m but as I put retaining on no one can see it. Now I have to check the centering which should be the same or slightly improves.
BTW, the guy didn't charge me anything as we are customers of this shop more than 20 years. Very nice of him. Should be mention that I have to use slip on lens caps as apparently there aren't enough threads to put on original caps. Extra blank filter should solve this problem in case that I want to put another filter on the lens.
I would like to add a fourth option to Fred's list - a local optometrist quickly and cheaply (NZ$35) edge ground the Optosigma filter down from its original 50 mm diameter to c. 46 mm on his glazing machine, custom fitting it to the rebate in the cheap 49 mm filter I bought and disassembled. He was initially concerned that the glass might be toughened, but an email to AusOptics brought a swift confirmation that this was not the case. The lens coating has survived the process in good shape.
Once I got it home, I initially held it in place with the original retaining ring. This worked okay, but left too little thread for a second filter, so I now have it held in place with a 49-52mm stepup ring, which has the added advantage of allowing me to use 52 mm filters in common with my Loxias.
My bet if you still want to use a hood you would need a 49 slim empty to start the setup to get the threading past the hood mount. Do you think you made it too small at 46mm instead of like 47 to just go straight to a 49mm empty holder and it's retaining ring
GMPhotography wrote:
My bet if you still want to use a hood you would need a 49 slim empty to start the setup to get the threading past the hood mount. Do you think you made it too small at 46mm instead of like 47 to just go straight to a 49mm empty holder and it's retaining ring
You're on the money as always, Guy. We carefully measured the rebate set into the bottom of the empty filter case, and it was about 46.3 mm, so the optometrist did the edge grinding in steps to fit snugly into that. Leaving it bigger would have left it sitting up too far above the back of the mount, reducing the amount of thread available for the retaining ring.
So with the filter in place I see two options. If not wanting to use additional filters, then the original retaining ring is fine, and the filter sits well recessed within the existing hood, with the hood performing its intended purpose. But if wanting to use other filters (PCL, grads, etc.) then the thickness of the filter results in there being too little thread for another filter to grip to once the retaining ring is fitted. That's why I went to the 49-52 setup, but as I discovered last night, when the step-up is fitted, the combination of 49 mm filter holder and step-up can't screw fully into place because the step-up ring hits the lens hood. Adding a low profile blank 49 mm filter mount would fix this.
HaruhikoT wrote:
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. ...Show more →
Thanks for the MTF link, your reasoning makes sense. I also tested the G28 with
the recommended filter. The results are very good (as also others have shown),
I think especially considering the current G28 prices. So thank you very much
for developing this solution!
tormoder wrote:
Thanks for the MTF link, your reasoning makes sense. I also tested the G28 with
the recommended filter. The results are very good (as also others have shown),
I think especially considering the current G28 prices. So thank you very much
for developing this solution!
Tormod: Practical question - how did you buy the SLB 50-5000PM here in Norway? Did you use OptoSigma directly or are there other distributers we can use?
OleAndre wrote:
Tormod: Practical question - how did you buy the SLB 50-5000PM here in Norway? Did you use OptoSigma directly or are there other distributers we can use?
There are plenty of manufacturers of planoconvex lenses, so I would seek for alternatives. There is nothing that says Optosigma are the best or anything like that. Just that it's been proven to yield good results, that's all. But why wouldn't a similar lens from a different brand do it just as well?
OleAndre wrote:
Tormod: Practical question - how did you buy the SLB 50-5000PM here in Norway? Did you use OptoSigma directly or are there other distributers we can use?
Ole, here is how process works from Finland:
1. Create order via OptoSigma Europa webpage https://www.global-optosigma.com/en_eu/
2. Wait that salesguy gets back to you via email
3. Pay via IBAN
4. Wait that salesguy gets back with final order confirmation and promised shipping date
5. Wait that the lenses arrive
On my case I did 1st step 19th Feb, 2nd and 3rd step on 20th Feb and 4th step 21st Feb, when they promised to deliver 10th March. I'm currently in step 5...
Norway is not in EU, so I would assume that you don't need to pay VAT, but you may have to pay some custom fees.
Samuli Vahonen wrote:
Ole, here is how process works from Finland:
1. Create order via OptoSigma Europa webpage https://www.global-optosigma.com/en_eu/
2. Wait that salesguy gets back to you via email
3. Pay via IBAN
4. Wait that salesguy gets back with final order confirmation and promised shipping date
5. Wait that the lenses arrive
On my case I did 1st step 19th Feb, 2nd and 3rd step on 20th Feb and 4th step 21st Feb, when they promised to deliver 10th March. I'm currently in step 5...
Norway is not in EU, so I would assume that you don't need to pay VAT, but you may have to pay some custom fees.
Makten wrote:
There are plenty of manufacturers of planoconvex lenses, so I would seek for alternatives. There is nothing that says Optosigma are the best or anything like that. Just that it's been proven to yield good results, that's all. But why wouldn't a similar lens from a different brand do it just as well?
You are probably right, but since we know how well the OptoSigma lens is working on the Distagon 35/1.4 ZM, I don't really feel like taking any chances
Disclaimer: I am highly risk averse person in general
Makten wrote:
There are plenty of manufacturers of planoconvex lenses, so I would seek for alternatives. There is nothing that says Optosigma are the best or anything like that. Just that it's been proven to yield good results, that's all. But why wouldn't a similar lens from a different brand do it just as well?
Well, we know that similarly specified pc lenses from Optosigma and Eksma behave differently thanks to BastianK, so trying one that hasn't been tested is risky, albeit good for the community!
OleAndre wrote:
Tormod: Practical question - how did you buy the SLB 50-5000PM here in Norway? Did you use OptoSigma directly or are there other distributers we can use?
Best wishes,
Ole
Ole: Yes, I ordered it directly from OptoSigma Europe based in France using the procedure described by Samuli. They were in general very helpful and responsive. They shipped the lens using UPS, and I had to pay VAT (MVA) and a small fee (utleggsprovisjon) on import.
I just received my opto-sigma lens for my 35/1.4ZM and have a few questions. Can the lens be inserted in either direction? If not, how do I know which side should be facing out? Also, my current setup using a 49-55, 55-52 and 52mm retaining ring results in the Opto-sigma having some play where the retaining ring doesn't quite tighten down to keep the opto-sigma secure. Do I need to try other rings?
rji2goleez wrote:
I just received my opto-sigma lens for my 35/1.4ZM and have a few questions. Can the lens be inserted in either direction? If not, how do I know which side should be facing out? Also, my current setup using a 49-55, 55-52 and 52mm retaining ring results in the Opto-sigma having some play where the retaining ring doesn't quite tighten down to keep the opto-sigma secure. Do I need to try other rings?
Thanks in advance!
Bob, I found that the best way to tell the surfaces apart was to lay it down on the tissue wrapping on a flat surface and press the edges to make it rock side to side - if the flat surface is on the tissue, you will see it creating even pressure across the whole surface, but if the curved surface is down, you will be able to shift the pressure on the underneath tissue around different parts of the lens. It's subtle but works. That curved surface needs to face the lens.
navmannz wrote:
Bob, I found that the best way to tell the surfaces apart was to lay it down on the tissue wrapping on a flat surface and press the edges to make it rock side to side - if the flat surface is on the tissue, you will see it creating even pressure across the whole surface, but if the curved surface is down, you will be able to shift the pressure on the underneath tissue around different parts of the lens. It's subtle but works. That curved surface needs to face the lens.
Sorry I can't help on the other...
-John
Wow, that's a subtle difference isn't it? I can feel the difference but the rocking side to side is so small that if you lay it on something like a this micro fiber cloth, there is no rocking on either side. However, once I laid it on the tissue paper on a hard surface the difference can be felt.
