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Langstrum
Joined: 16 Feb 2014
Posts: 351
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 Posted: Tue Jul 25, 2017 2:57 am Post subject: SLR Magic 25/1.4, 35/1.2, 75/1.4 reviews and related issues |
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Langstrum wrote:
I want to share my recent reviews of SLR Magic 25mm f/1.4, 35mm f/1.2, and 75mm f/1.4 CINE lenses that were published on SAR (maybe some people here already read them). They're compact and uniform lenses with some features better than Samyang, and currently I'm satisfied to replace my Samyang lenses with SLR Magic.
SLR Magic 25mm f/1.4 CINE review: http://www.sonyalpharumors.com/slr-magic-25mm-f1-4-cine-review-comparisons/
SLR Magic 35mm f/1.2 and 75mm f/1.4 CINE review and battle with Samyang 35mm f/1.4 and 85mm f/1.4: http://www.sonyalpharumors.com/slr-magic-cine-35mm-f1-2-75mm-f1-4-battle-samyang-counterparts
There are few issues I found during the testing period and I had some explanations, but I want to ask experienced MF lenses users here to get more insights.
1. The changes in color rendition by stopping down: it's not the first time I encountered this but I don't have an actual explanation. That phenomenon usually occurs when I close the aperture about 1 or 2 stops from the widest one and it happened with few fast lenses. At wide open the lens can cast some warm color and when I stop down, the color is colder, and vice versa. To make sure it's the property of the lens itself, I shot in RAW and fix the temperature and tint value of the photos, and they still show the difference (even though it's negligible to many people). In the photo below, SLR Magic 75mm showed warm color at wide open, but at f/11 it's cooler, and with SLR Magic 35mm it's slightly warmer by stopping down (in fact, they're different already from f/2). Do you think it's the actual change in color rendition or just because it became less saturated with smaller apertures?
2. SLR Magic 35/1.2 showed focus shifting issue, but only in the center part. It means when I stopped down the lens, the focus point became closer to me, but it didn't happened when I tested the edge performance. I thought that's because of the change in the field curvature that it's more flattened by stopping down so it affects only the center part where the field curvature is more curved. But I'm not sure that is an actual mechanism or not.
3. Does vignetting affect T-stop? What I think is the lower light transmission in the corner attribute to the reduced T-stop so lenses with strong vignette at wide open only can only reach certain T-stop below the 100% transmission value. In my test, I found out that Sony FE 28mm lens has strong vignette at f/2 but it was corrected by the camera, but DxO Mark rated it at T2. It's very confusing to me now.
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Camera: Sony A7 mark III, A6300
AF Lenses:
Canon EF 50/1.8; EF 200/2.8 L, EF 200/1.8 L, EF 300/4 L Sony E mount SEL 50/1.8 OSS, SEL 16/2.8 Fuji X mount XF 35/1.4 R
MF Lenses: Peleng MC 8/3.5, 17/2.8 Samyang 14/T3.1, 35/T1.5, TS 24/3.5 ED, 85/T1.5, Polar 85/1.4 Auto Revuenon 28/2.8; MC 50/1.4 Vega11U 50/2.8 Carl Zeiss Tessar 50/2.8 (exakta mount) Auto Chinon 50/1.9 Zenitar ME1 50/1.7 Sears Auto Sears 55/1.4; Sears 135/2.8 Auto Yashinon DX 50/1.4; Tomioka 50/1.2 SMC Pentax 50/1.7; 50/1.4 Canon FD 50/1.4 S.S.C; 55/1.2 S.S.C; FD 50/1.2 L; FD 85/1.2 L; 85/1.2 S.S.C Aspherical; FD 80-200/4 L 300/2.8 S.S.C Fluorite FD 300/2.8 L FD 200/1.8 LCosina-S 50/1.2 Helios Helios 44 Chrome f/22, 44-2, 44-3, 44M-4, 44M-7 (58/2), Helios-40 85/1.5 Jupiter Jupiter-9 85/2; Jupiter-37A 135/3.5; Jupiter-21M 200/4 Nikon Ai 105/2.5 Tairs-3S 300/4.5
Voigtlander 15/4.5 Aspherical; Ultron 35/1.7
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tb_a
Joined: 26 Jan 2010
Posts: 3678
Location: Austria
Expire: 2019-08-28
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| Posted: Tue Jul 25, 2017 8:31 am Post subject: |
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tb_a wrote:
To me it appears that the SLR Magic lens simply has a warmer color rendering than the Samyang lens. I quite often see this phenomena when I compare lenses. Causes for this are most probably different coatings or different kind of glass.
Furthermore the contrast of the Samyang lens seems to be better at F1.4 compared to the SLR Magic one. Obviously the Samyang is the better lens, at least for my taste.
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Thomas Bernardy
Manual focus lenses mainly from Minolta, Pentax, Voigtlaender, Leitz, Topcon and from Russia (too many to be listed here). |
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Langstrum
Joined: 16 Feb 2014
Posts: 351
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| Posted: Tue Jul 25, 2017 8:47 am Post subject: |
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Langstrum wrote:
| tb_a wrote: |
To me it appears that the SLR Magic lens simply has a warmer color rendering than the Samyang lens. I quite often see this phenomena when I compare lenses. Causes for this are most probably different coatings or different kind of glass.
Furthermore the contrast of the Samyang lens seems to be better at F1.4 compared to the SLR Magic one. Obviously the Samyang is the better lens, at least for my taste. |
Yes, Samyang is better at f1.4, considering both sharpness and contrast, and even down to f4-f5.6, and it's not as warm as Samyang. My question is about using the same lens but stopping down can slightly change the color rendering, i.e. cooler or warmer. I can understand that lenses with different coatings render colors differently, but I'm not sure why the same lens can change the color rendition. What I have in my mind is because of vignetting and different behaviors of wavelengths.
_________________
Camera: Sony A7 mark III, A6300
AF Lenses:
Canon EF 50/1.8; EF 200/2.8 L, EF 200/1.8 L, EF 300/4 L Sony E mount SEL 50/1.8 OSS, SEL 16/2.8 Fuji X mount XF 35/1.4 R
MF Lenses: Peleng MC 8/3.5, 17/2.8 Samyang 14/T3.1, 35/T1.5, TS 24/3.5 ED, 85/T1.5, Polar 85/1.4 Auto Revuenon 28/2.8; MC 50/1.4 Vega11U 50/2.8 Carl Zeiss Tessar 50/2.8 (exakta mount) Auto Chinon 50/1.9 Zenitar ME1 50/1.7 Sears Auto Sears 55/1.4; Sears 135/2.8 Auto Yashinon DX 50/1.4; Tomioka 50/1.2 SMC Pentax 50/1.7; 50/1.4 Canon FD 50/1.4 S.S.C; 55/1.2 S.S.C; FD 50/1.2 L; FD 85/1.2 L; 85/1.2 S.S.C Aspherical; FD 80-200/4 L 300/2.8 S.S.C Fluorite FD 300/2.8 L FD 200/1.8 LCosina-S 50/1.2 Helios Helios 44 Chrome f/22, 44-2, 44-3, 44M-4, 44M-7 (58/2), Helios-40 85/1.5 Jupiter Jupiter-9 85/2; Jupiter-37A 135/3.5; Jupiter-21M 200/4 Nikon Ai 105/2.5 Tairs-3S 300/4.5
Voigtlander 15/4.5 Aspherical; Ultron 35/1.7
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tb_a
Joined: 26 Jan 2010
Posts: 3678
Location: Austria
Expire: 2019-08-28
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| Posted: Tue Jul 25, 2017 9:19 am Post subject: |
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tb_a wrote:
| Langstrum wrote: |
| My question is about using the same lens but stopping down can slightly change the color rendering, i.e. cooler or warmer. I can understand that lenses with different coatings render colors differently, but I'm not sure why the same lens can change the color rendition. What I have in my mind is because of vignetting and different behaviors of wavelengths. |
I don't think so. It just appears to be different when stopped down as the contrast increases substantially. At least that is my explanation and that is what I am seeing when I compare lenses with different color renderings at different apertures.
However, I'm no physicist. 
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Thomas Bernardy
Manual focus lenses mainly from Minolta, Pentax, Voigtlaender, Leitz, Topcon and from Russia (too many to be listed here). |
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