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Thank you, speak volumes, at least if we are talking f/5.6 only.Here are some boring and quick wallpaper shots using the 18, 25, 35, and 50 mm Zeiss lenses. (...)
You are welcome Jonas. I also shot wide open (lens dependent f/2, f/2.8, f/4) and all at f/4. Same conclusion.Thank you, speak volumes, at least if we are talking f/5.6 only.
I don't mind boring targets. They can tell us a lot.
I do not understand what this is all about. Focus shift????I mentioned the f/5.6 comparison because I got another result today. I wonder what you can do out of this:
Earlier today I received a Cosina Voigtländer M-mount lens, the CV28/2 Ultron. I had high hopes for this lens as I have seen a lot great images taken with it (at flickr that is).
Pretty early when playing with it I noticed a (quite severe) focus shift problem. Then I aimed the camera towards a book shelf to see what the borders/corners would be like. I shot two series; one without refocusing between the exposures and then another one where I did refocus thinking of the mentioned focusing shift.
The images below are from the second series - refocusing was, simply put, necessary with this lens.
First an overview:
Then, in order, f/2 - f/5.6 100% crops. There is no sharpening applied to the crops:
I can't believe the lens is supposed to behave this way and the images I have seen (Bessa and M8 images) didn't prepare me for this. There is no difference between the left and right side or any of the corners.
Now the lens will go back anyway due to the focus shift. I knew about the focus shift but it was worse than anything I had read at the rangefinder forum.
What do you think about all this? Should I buy Zeiss lenses instead?
I have this lens also and yes, it does focus shift. I get around it by either shooting wide open or stopping down to about f/8 for landscapes on the M8. However, focus shift, as Cindy noted, is really a non-issue on the G1. What you are seeing with your series of bookshelf shots is exactly the same as what I found with my wallpaper shots and the Zeiss lenses. This peripheral distortion/smearing seems to be most prominent in the 20 to 35 mm focal lengths that I have tested on the G1 with the M adapter and it is worse at wider apertures. It has nothing to do with focus shift.I mentioned the f/5.6 comparison because I got another result today. I wonder what you can do out of this:
Earlier today I received a Cosina Voigtländer M-mount lens, the CV28/2 Ultron. I had high hopes for this lens as I have seen a lot great images taken with it (at flickr that is).
Pretty early when playing with it I noticed a (quite severe) focus shift problem. Then I aimed the camera towards a book shelf to see what the borders/corners would be like. I shot two series; one without refocusing between the exposures and then another one where I did refocus thinking of the mentioned focusing shift.
I can't believe the lens is supposed to behave this way and the images I have seen (Bessa and M8 images) didn't prepare me for this. There is no difference between the left and right side or any of the corners.
Now the lens will go back anyway due to the focus shift. I knew about the focus shift but it was worse than anything I had read at the rangefinder forum.
What do you think about all this? Should I buy Zeiss lenses instead?
Carl and Guy, thanks for the input and clarification.I have this lens also and yes, it does focus shift. I get around it by either shooting wide open or stopping down to about f/8 for landscapes on the M8. However, focus shift, as Cindy noted, is really a non-issue on the G1. What you are seeing with your series of bookshelf shots is exactly the same as what I found with my wallpaper shots and the Zeiss lenses. This peripheral distortion/smearing seems to be most prominent in the 20 to 35 mm focal lengths that I have tested on the G1 with the M adapter and it is worse at wider apertures. It has nothing to do with focus shift.
It is known the CV28/2 suffer from some focus shift. I mentioned it most of all to make sure anyone reading the post should know I knew about it, and hence did refocus between the shots.I do not understand what this is all about. Focus shift????
If I focus the CV28/2 with the G1 (with the lens opened up to f/2) and then stop down the focus plane has moved. That is focus shift. With the CV28/2 stopping down to f/8 didn't help; the focus plane has moved away so far that the DOF doesn't cover the are first focused at. That was way more severe than I expected.I have / have had lenses with focus shift on my M8. These are fast lenses in my case. The Noctilux was the worst. I had to focus it (when wide open) and then give it a little twist to the right. Stopped down, there was no shift. The problem was that the focus patch indicated that the lens was in perfect focus when it was at f/1, but it wasn't.
With the G1, focus shift is not a problem. Just focus the lens for the shot and it is always perfect. This is the one of the reasons that I like the G1 so much. When you focus, you can be sure that you are in focus.
My post was about smearing corners and I hope we are talking about the same thing. Maybe i shouldn't have mentioned about the focus shift at all.Smearing corners is a different thing, but I haven't seen it in my photos yet. Thanks Carl for doing testing on this. I am interested in taking photos, not testing, so I'll wait to hear what info others gather.
If I'm missing something here, please enlighten me.
To anyone:I have this lens also and yes, it does focus shift. I get around it by either shooting wide open or stopping down to about f/8 for landscapes on the M8. However, focus shift, as Cindy noted, is really a non-issue on the G1. What you are seeing with your series of bookshelf shots is exactly the same as what I found with my wallpaper shots and the Zeiss lenses. This peripheral distortion/smearing seems to be most prominent in the 20 to 35 mm focal lengths that I have tested on the G1 with the M adapter and it is worse at wider apertures. It has nothing to do with focus shift.
Hi,(...)
The question I have here and maybe the case is if you focused wide open than left that alone and just stopped down and shot WITHOUT refocusing at the working aperture than the focus shift could occur. In this case you really need to refocus each time with the G1 at the working aperture
Hi Cindy,Jonas, Thank you for your explanation of your method. Did you use a tripod?