- Posts: 37
- Joined: Wed Jul 03, 2013 11:51 am
Hi all, I am new to this forum. Nice to meet you all! People (John Brawley?)have commented that the Voigtlander 17.5 0.95 is soft and bloomy when wide open. I own this lens myself and never find that it is the case on my old GH2. It is actually very usable and quite sharp at the centre on my GH2, and it is my go-to night lens. Last week I have got my new BMCC MFT so I decided to test it out. The result is shockingly different from my GH2. The BMCC MFT is a lot more bloomy and soft with the Voigtlander 17.5 wide open, than on the GH2. Almost make the lens unusable at wide open.
I have attached the test result. The left side is 2.5K RAW from BMCC + Voigtlander 17.5 wide open, 1:1 crop to the centre of the lens. Distance to subject is around 1m. The right side is photo RAW from GH2, crop and scale to match the BMCC frame. Position of the camera is the same, lens setting is the same, even shutter speed is the same too. Both opened in ACR and scaling is done in Photoshop. No post sharpening.
The BMCC picture (left) is a lot more bloomy and soft and lack of contrast, while on the GH2 you can clearly see the texture of the paper and even read the text. You may argue that the GH2 photo sensor is a lot more resolution and it preserves that resolution when it scales down. But if you look at the edge of the bottle and the contrast of the text, if I didn't do the test myself I would have thought it's a completely different lens!
If I stop down the lens to f1.4 the "bloominess" seems to be gone and match with how the lens looks on GH2. But at 0.95, looking at the edge of the bottle, it almost looks like there is another layer of reflection inside the camera. While I see the area around the BMCC sensor is kind of reflective and is not exactly all black (unlike GH2), I tried matting the rear of the lens and see if it affects the bloominess. What I find is it does, but by the time it kill that bloominess, the image appears darker. So it's not all that different from stoping down the aperture. So I can't help but to conclude it is a design flaw with the area around the sensor reflecting an extra layer of light. Maybe it's the sensor glass? Or maybe just the general non black reflective areas around the sensor?
Please chimp in your thoughts about this! What might be the problem and how might we fix this? I have the Voightlander 25mm 0.95 and it doesn't do that wide open. Have you guys experience something like that with other lens?
I have attached the test result. The left side is 2.5K RAW from BMCC + Voigtlander 17.5 wide open, 1:1 crop to the centre of the lens. Distance to subject is around 1m. The right side is photo RAW from GH2, crop and scale to match the BMCC frame. Position of the camera is the same, lens setting is the same, even shutter speed is the same too. Both opened in ACR and scaling is done in Photoshop. No post sharpening.
The BMCC picture (left) is a lot more bloomy and soft and lack of contrast, while on the GH2 you can clearly see the texture of the paper and even read the text. You may argue that the GH2 photo sensor is a lot more resolution and it preserves that resolution when it scales down. But if you look at the edge of the bottle and the contrast of the text, if I didn't do the test myself I would have thought it's a completely different lens!
If I stop down the lens to f1.4 the "bloominess" seems to be gone and match with how the lens looks on GH2. But at 0.95, looking at the edge of the bottle, it almost looks like there is another layer of reflection inside the camera. While I see the area around the BMCC sensor is kind of reflective and is not exactly all black (unlike GH2), I tried matting the rear of the lens and see if it affects the bloominess. What I find is it does, but by the time it kill that bloominess, the image appears darker. So it's not all that different from stoping down the aperture. So I can't help but to conclude it is a design flaw with the area around the sensor reflecting an extra layer of light. Maybe it's the sensor glass? Or maybe just the general non black reflective areas around the sensor?
Please chimp in your thoughts about this! What might be the problem and how might we fix this? I have the Voightlander 25mm 0.95 and it doesn't do that wide open. Have you guys experience something like that with other lens?
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