Having followed this thread for a while, and seeing HaruhikoT's simulation results for the Leica 35mm Summilux Asph (non-FLE) here, decided to buy the OptoSigma SLB-50-5000PM lens. Having assembled the filter, below are my test shots with and without the filter on a Sony A7II. Definite corner improvement and with the usual dip in the mid-frame as expected...
I picked up a Contax G28 cheaply (currently on the way) and I have the option of purchasing a reasonably priced G21 locally.
Therefore I would like to order the Opto-Sigma Plano-Convex 1.5 m lens.
However, I have not found a place to order one and have it delivered to Germany. Email enquiries to Opto-Sigma Europe have not been replied to.
Does anyone have a source where I can order as a private individual?
I actually work in a large research lab and we order all sorts of optical components, but our finance department has no provisions (at least no simple one) for ordering things through the lab and paying for them through my private account so I can't use that path.
I just added the lenses to "cart", and then ordered the items from "cart". There is also option to ask quotation in website, but I didn't see any point doing that; I'm one-time customer who ordered 5 lenses -> they have no reason to give me 50% discount... So I skipped that and ordered directly.
Then somebody emailed how to pay (IBAN stuff), and I paid and then I got delivery date confirmed. They don't have modern webshop where you can pay with credit card / Paypal, and I understand it as they are normally NOT dealing with normal consumers, they are 99,999% in B2B market. But they still sell to individual people, only difference is that for those orders they need to include VAT.
Then just waited and lenses were delivered to my home. Very easy, and no customs etc. hazzle as they ship from France.
craygc wrote:
Having followed this thread for a while, and seeing HaruhikoT's simulation results for the Leica 35mm Summilux Asph (non-FLE) here, decided to buy the OptoSigma SLB-50-5000PM lens. Having assembled the filter, below are my test shots with and without the filter on a Sony A7II. Definite corner improvement and with the usual dip in the mid-frame as expected...
Received the 1.5m lens from Optosigma yesterday. I tried mounting it in a combo of 52mm-55mm step-up and 55mm to 52mm step down rings, but onfortunately the latter one is not thick enough to retain the lens.
I came up with a temporary solution
The correction lens actually fits perfectly in the lens hood, I just need a better way to retain it than blue-tak.
(I hope the blu-tak doesn't cause any coating damage even though it would be purely cosmetic as it is only touching the lens at the very edges anyway).
Maybe a large stiff O-ring would do the job or some other retaining ring that fits inside the hood. The baffles in the hood look almost like threads.
In combination with the nice hood caps of the Contax system the hood could stay always on and the filter would be protected.
I did a handful of test shots and can see noticeable improvement. However, I do not reach infinity with the Techart-GA3 anymore. I will try and remove the very thin shim that is under the optical block but I have feeling that it won't be enough. The lens body on my copy has quite some play (was sold as defective but with pristine optics). Have another lens body in the mail so I can see whether there is some variation with respect to the infinity stop.
You should reach infinity with a 1.5m lfilter on the Biogon G28. Those lenses focus normally well past infinity to avoid that the AF mechanism hits the hard stop. I had no trouble with this same Optosigma 1.5m. filter so probably your lens is somehow damaged. When you remove the filter, are you able to focus noticeably past infinity with the GA3 in manual focus or it's a close shave ?
artur5 wrote:
so probably your lens is somehow damaged. When you remove the filter, are you able to focus noticeably past infinity with the GA3 in manual focus or it's a close shave ?
I know that the lens is in fact slightly defective. The focusing mechanics that move the optical block back and forth have slight play in it. I did have only a few minutes to play with the lens today and I noticed that I can push the optical block a bit further towards the film plane by pressing at the front of the lens. This then brings me much closer to infinity.
Anyway, another lens body (without the optical block) is in the mail to me. So it sounds that once I place the optics in this undamaged lens body I will not just remove the play but probably also reach infinity. This will be very welcome.
I can already tell that I'm sufficiently happy with the image quality that the 28mm Biogon delivers in combination with the front filter so that it will replace my C/Y Distagon 28mm 2.8.
I'm Paul from Optosigma Europe. I just went here to let you know that we released a new website for European customers. It is now possible to buy directly from our website (by credit card). We still are working on the optimization, it may miss some articles, but you can already buy online and there isnt any minimum price.
I just added the lenses to "cart", and then ordered the items from "cart". There is also option to ask quotation in website, but I didn't see any point doing that; I'm one-time customer who ordered 5 lenses -> they have no reason to give me 50% discount... So I skipped that and ordered directly.
Then somebody emailed how to pay (IBAN stuff), and I paid and then I got delivery date confirmed. They don't have modern webshop where you can pay with credit card / Paypal, and I understand it as they are normally NOT dealing with normal consumers, they are 99,999% in B2B market. But they still sell to individual people, only difference is that for those orders they need to include VAT.
Then just waited and lenses were delivered to my home. Very easy, and no customs etc. hazzle as they ship from France.
Could anyone post some real-world photos that they like with the Contax G28+ 1.5m OptoSigma combo (as opposed to lens tests)? I have this lens and used it extensively on e-mount APS-C, but I'm wondering if it's worth the hassle/cost on the A7. I've got a couple of other decent 28mm options.
alwang wrote:
Could anyone post some real-world photos that they like with the Contax G28+ 1.5m OptoSigma combo (as opposed to lens tests)? I have this lens and used it extensively on e-mount APS-C, but I'm wondering if it's worth the hassle/cost on the A7. I've got a couple of other decent 28mm options.
For me this is the best 28mm at the moment. Biogon provides better (according to my preferences) DOF -> boke transitions and boke than Distagons. I like ZE/ZF 2/28 very much, but the outward field curvature ruins it for me (something pops up from background into focus from what should be in smooth boke - could not care less if something is not sharp in corners, but something which should be out of focus suddenly coming into focus totally ruins it). C/Y Distagon 2.8/28 is quite good on Kolari v2, but outer edges have very steep dive for outer field curvature. Leica R 28mm f/2.8 v2 is good otherwise but I find it's boke awful. So G28 is "the" 28mm for me at the moment.
I have shoot a lot with this combo, but it seems that I have not processed to photos to internet. On summer holiday I had two "sets" of lenses with me: 1) G21, G28, G45 and G90 2) ZM18, ZM25, ZM35, Leica90APO. And I'll will be posting them (to FE-megathread) during fall when I have time and motivation for computer work - this far I have processed only 1st day photos of ~20 shoot days, and 1st day I used the ZM-"set" so no "new" G28 from there yet. I did search online and I have only these available, EXIF is perfect, but if you don't have EXIF-data viewer in your browser open image to new tab, and see from JPG's filename what was the aperture etc.
EDIT: Also one thing to keep in mind: unless you have A7r mkII you need to use Flat Field plugin in Lightroom to get rid off the color cast. A7r mkII has backlit CMOS sensor, and A7, A7r, A7 mkII will cause color casts to edges of images due to CFA(Color Filter Array) structure needed for "frontlit" CMOS sensor. I find this rather annoying - mostly because I don't use Lightroom but I need to use it for G21, G28, ZM25, ZM18 photos (in some circumstances I might use it for ZM 2/35 and ZM 1.5/50 as well).
So meanwhile I received a new (used) lens body for my Contax G 28. This one is not defective (no wobble) and after removing a shim I still can't quite focus to infinity with the Techart GA3 adapter when the PCX 1.5m lens is in place - despite being able to focus quite a bit past infinity without the filter.
However, when mounting the lens on my cheapo manual adapter I can focus past infinity even with the filter on it. I can tell just from looking at the lens that the manual adapter brings the optical group much closer to the film plane than the Techart.
In practical shooting I found that the AF of the Techart GA-3 which appears to do a reasonable job in indoor and urban situation often fails for the G 28 in outdoor settings (with lots of fine texture and contrast). Therefore the G28 will probably simply stay on the manual adapter. I'm very pleased with the results.
alwang wrote:
Could anyone post some real-world photos that they like with the Contax G28+ 1.5m OptoSigma combo (as opposed to lens tests)? I have this lens and used it extensively on e-mount APS-C, but I'm wondering if it's worth the hassle/cost on the A7. I've got a couple of other decent 28mm options.
Here's a couple with the A7ii from a few days ago.
edit: and another one
Note that the last one wasn't fully focused to infinity (I only brought the Techart-Adapter on this trip) and was stopped down to f11 to get the distant peaks into focus.
edit:
here the AF didn't focus where I wanted to, but you can see that the bottom left corner is tack sharp and you can see some bokeh
edited again:
I would also like to see some real-world examples with the G21 + filter as I have the option to buy a G21 locally but I'm still on the fence as it is quite a bit of money.
Thank you both very much for posting these examples. Both Samuli's close-range photos of the tree trunks and OpticalFlow's last photo (with the hat in the lower left corner) match my normal use case exactly. I'm really impressed, in the case of Samuli's samples, that such even performance across the frame was achieved at f/5.6. Now I'm even more impatiently awaiting the arrival of the PCX 1.5m lens I've ordered.
Samuli Vahonen wrote:
For me this is the best 28mm at the moment. Biogon provides better (according to my preferences) DOF -> boke transitions and boke than Distagons. I like ZE/ZF 2/28 very much, but the outward field curvature ruins it for me (something pops up from background into focus from what should be in smooth boke - could not care less if something is not sharp in corners, but something which should be out of focus suddenly coming into focus totally ruins it). C/Y Distagon 2.8/28 is quite good on Kolari v2, but outer edges have very steep dive for outer field curvature. Leica R 28mm f/2.8 v2 is good otherwise but I find it's boke awful. So G28 is "the" 28mm for me at the moment.
I have shoot a lot with this combo, but it seems that I have not processed to photos to internet. On summer holiday I had two "sets" of lenses with me: 1) G21, G28, G45 and G90 2) ZM18, ZM25, ZM35, Leica90APO. And I'll will be posting them (to FE-megathread) during fall when I have time and motivation for computer work - this far I have processed only 1st day photos of ~20 shoot days, and 1st day I used the ZM-"set" so no "new" G28 from there yet. I did search online and I have only these available, EXIF is perfect, but if you don't have EXIF-data viewer in your browser open image to new tab, and see from JPG's filename what was the aperture etc.
EDIT: Also one thing to keep in mind: unless you have A7r mkII you need to use Flat Field plugin in Lightroom to get rid off the color cast. A7r mkII has backlit CMOS sensor, and A7, A7r, A7 mkII will cause color casts to edges of images due to CFA(Color Filter Array) structure needed for "frontlit" CMOS sensor. I find this rather annoying - mostly because I don't use Lightroom but I need to use it for G21, G28, ZM25, ZM18 photos (in some circumstances I might use it for ZM 2/35 and ZM 1.5/50 as well).
OpticalFlow wrote:
So meanwhile I received a new (used) lens body for my Contax G 28. This one is not defective (no wobble) and after removing a shim I still can't quite focus to infinity with the Techart GA3 adapter when the PCX 1.5m lens is in place - despite being able to focus quite a bit past infinity without the filter.
However, when mounting the lens on my cheapo manual adapter I can focus past infinity even with the filter on it. I can tell just from looking at the lens that the manual adapter brings the optical group much closer to the film plane than the Techart.
In practical shooting I found that the AF of the Techart GA-3 which appears to do a reasonable job in indoor and urban situation often fails for the G 28 in outdoor settings (with lots of fine texture and contrast). Therefore the G28 will probably simply stay on the manual adapter. I'm very pleased with the results. ...Show more →
Just noticed that STC Optics have released Sony versions of their Clip Filter series, and that on their site one of the things that they say that it does is: "The color shift issue that may occur due to the wide angle SLR lens in peripheral areas of the image also can be solved."
Has anyone tried these, and does it help with any of the issues raised in this thread?
