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08-27-2014, 06:00 PM   #151
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Harder to focus... but much harder to find. The 85mm makes more sense to me...

08-27-2014, 08:46 PM   #152
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QuoteOriginally posted by cali92rs Quote
I was going to be all over a Samyang f1.2....a f1.4 doesn't do anything for me because they are a dime a dozen, well not quite, but still.
Oh contraire! While they are a dime a dozen, the same optical design (6 elements in 4/5 groups, double-gauss) is in almost all of them dating back to the late 1950s, meaning they almost all behave very similarly. This Samyang is a new beast entirely (9 elements in 6 groups, no clue on layout), that is in the new arena with the Zeiss Otus and Sigma Art (both of which are entirely new designs).

These last few years have been revolutionary to the 50mm lens, and Samyang has now made it even more affordable than Sigma! Of course we have to wait and see the reviews come in, but given Samyang's track record and those sample images, I'm not too concerned.

This is incredible news - much more exciting than the K-S1 by a long shot. This may be the first lens I ever pre-order, and you can bet I'll do a side-by-side with the my favorite double-gauss lenses - the A50/1.2 and the auto-takumar 55/2.2 (circa 1959 mind you!).
08-28-2014, 12:01 AM   #153
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QuoteOriginally posted by Clavius Quote
I would insta-buy a DFA 50mm 1.2, just because I'm still so astonished myself with the A 50mm 1.2.
Yes, well said, I would too, while I'm saving for an A-50 f1.2, if Samyang bring out an above average 50 1.2 I'd probably jump on it
09-04-2014, 10:00 PM   #154
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Keep in mind digital sensors lose considerable ability to gather light efficiently past about f/2.8. By the time you get past about f/2, efficiency drops down to about 50% or less - depending on the design of the particular sensor. I guess there can be some bragging rights involved in saying you have an f/1.2 lens - but the amount of additional light gathered really is marginal (not to mention valid comparative image quality concerns at more typical f-stops) and most often not worth the loss in rendering quality.

However, I am impressed with the Samyang line - especially the unique qualities of the 8mm stereographic which has a very natural projection in most situations compared to the extreme distortions of rectilinear or typical fisheye. I just don't see much reason to replace my small, smooth 50mm f/1.4 even if the large Samyang does fairly well in IQ.

09-05-2014, 08:45 AM   #155
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QuoteOriginally posted by Na Horuk Quote
Lets see a competition between Samyang 50mm, Sigma 50mm f1.4 art, and Zeiss Otus (though, since Otus is 55mm it has a slight advantage in bokeh). and Just for kicks, add the FA 50mm f1.4
better kick in the DA*55/1.4.

---------- Post added 5th Sep 2014 at 05:49 PM ----------

QuoteOriginally posted by cali92rs Quote
I was going to be all over a Samyang f1.2....a f1.4 doesn't do anything for me because they are a dime a dozen, well not quite, but still.
Keep in mind it's a T1.5 for a F1.4 lens. It means the light transmission is very very close of the theorical amount of light that should go trought.

If you look at the actual F1.4 50/55mm lenses, most of them are T1.7-1.8-2, which is between half a stop and a stop of difference.

To make it short, videographer have now a really "night eye" lens.
09-05-2014, 12:05 PM   #156
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QuoteOriginally posted by aurele Quote
Keep in mind it's a T1.5 for a F1.4 lens. It means the light transmission is very very close of the theoretical amount of light that should go through. If you look at the actual F1.4 50/55mm lenses, most of them are T1.7-1.8-2, which is between half a stop and a stop of difference.
I doubt those T stop numbers are accurate. The "cine" version of the Samyang lens 85/1.4 is also listed as T1.5, yet dxomark gives it a 1.7 in their tests. In fact, all of Samyangs "cine" versions have T-stops lower than what dxomark comes up with in their tests.
09-05-2014, 01:23 PM   #157
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QuoteOriginally posted by northcoastgreg Quote
I doubt those T stop numbers are accurate. The "cine" version of the Samyang lens 85/1.4 is also listed as T1.5, yet dxomark gives it a 1.7 in their tests.
Didn't DXO test the older, pre-UMC version?
09-05-2014, 07:15 PM   #158
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QuoteOriginally posted by northcoastgreg Quote
I doubt those T stop numbers are accurate. The "cine" version of the Samyang lens 85/1.4 is also listed as T1.5, yet dxomark gives it a 1.7 in their tests.
DXO stated the Sigma 18-35mm f/1.8 has an almost perfect 99% light transmission - but with my testing of this lens, I quickly noticed that this result is wrong. I tested the full APS-C imaging circle of the lens @ 18mm f/1.8 and vignetting knocks the effective transmission down to T=2.9*. DXO never mention the area of the lenses imaging circle they use to ascertain the light transmission of a lens. Or whether they weight it depending on the format the lens is intended to be used on.

* at the 18mm setting, vignetting reaches almost 3.5 stops in the corners.

09-06-2014, 09:27 AM   #159
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QuoteOriginally posted by lytrytyr Quote
Didn't DXO test the older, pre-UMC version?
Not for all the lenses. For example, according to the DXOmark, the Samyang "UMC" 16mm has a T stop of 2.5. Samyang gives that same lens a T stop rating of 2.2.

QuoteOriginally posted by Digitalis Quote
DXO stated the Sigma 18-35mm f/1.8 has an almost perfect 99% light transmission - but with my testing of this lens, I quickly noticed that this result is wrong.
That is baffling, and makes one wonder what's going on over at DXOmark. It's hard to believe that a lens with so much glass could have near perfect transmission. Yet they seemed to have tested the lens on both Canon and Nikon DSLRs, achieving T=1.8 with the Canon, and a T=1.9 with the Nikon.

QuoteOriginally posted by Digitalis Quote
at the 18mm setting, vignetting reaches almost 3.5 stops in the corners.
According to DXOmark,

QuoteQuote:
Both vignetting and chromatic aberration are also low, though, surprisingly, CA is more conspicuous in the corners at 24mm than at 18mm. Also worth mentioning is the excellent, mostly consistent 2TStop transmission measurement at full-aperture.
I've always had some suspicion of DXOmark's lens tests, but more on grounds of the significance of the tests, rather than their accuracy. Perhaps the suspicion needs to be extended to the accuracy.

Does this mean that DXOmark's measurements on Samyang lenses could be wrong? Possibly. But on the Samyang lenses, the DXOmark numbers strike me as more plausible than Samyang's own T-stop designations.
09-06-2014, 11:18 AM   #160
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It makes no sense to measure the entire image circle for the T-value. Because only the photons that actually hit a sensor matter. So measuring the image circle instead of the sensor is not practical since the sensor does not cover the image circle. It's the other way around. DXO-mark is not stupid.
09-06-2014, 12:01 PM   #161
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QuoteOriginally posted by D1N0 Quote
So measuring the image circle instead of the sensor is not practical since the sensor does not cover the image circle.
In fact the sensor DOES cover the image circle in the corner at least. The fact that the 18-35/1.8 does have a vigneting that is that huge is indeed quite a problem...
09-06-2014, 02:53 PM   #162
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QuoteOriginally posted by aurele Quote
In fact the sensor DOES cover the image circle in the corner at least. The fact that the 18-35/1.8 does have a vignetting that is that huge is indeed quite a problem...
It's not a problem. It's a fact. And when dxo measures 99% transmission the the vignetting will have been taken into account (but not vignetting outside of the sensor).
09-06-2014, 03:21 PM   #163
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QuoteOriginally posted by D1N0 Quote
It's not a problem. It's a fact.
Well, it is a fact, and it is a problem. If you prefer.

QuoteOriginally posted by D1N0 Quote
And when dxo measures 99% transmission the the vignetting will have been taken into account
I'm not quite sure about this. If you can bring up some info by DxO on this, i'm all ears.
09-06-2014, 07:00 PM   #164
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QuoteOriginally posted by D1N0 Quote
when dxo measures 99% transmission, the vignetting will have been taken into account
I don't think DXO are doing this - I think they are weighting the transmission based on the central 1/3rd of the lenses imaging circle.
09-06-2014, 07:17 PM   #165
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QuoteOriginally posted by Digitalis Quote
I don't think DXO are doing this - I think they are weighting the transmission based on the central 1/3rd of the lenses imaging circle.
Careful, your lazy mind might have to be educated.
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