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Forum: Lens Clubs
10-08-2010, 06:48 AM
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And how much is the difference, roughly?
You can make another test by setting your speed 1/2 stop faster for the Porst (e.g. 1/90 vs. 1/60 s). The Porst image should have the same brightness as the Takumar then.
The human eye is quite sensible to see slight differences in brightness if you switch back and forth.
The question is how much this difference is in EV steps. For my example above it was about 1/6 EV.
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Forum: Lens Clubs
10-08-2010, 01:18 AM
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Forum: Lens Clubs
10-02-2010, 04:20 AM
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Ok, I just compared the Revuenon 55/1.2 with the FA50/1.4.
One should expect the Revuenon to be half a stop brighter.
This is not the case.
ISO 200, fully open, 1/60 s
Both give about the same histogram, i.e. the same brightness of the image.
If I go up to 1/90 s for the Revuenon, the image is clearly darker.
I checked the images in Adobe Camera RAW where you can shift the exposure very acurately and I would say that the Revuenon is perhaps about 0,15 EV or 1/6 stop brighter.
This is what I expected: These no-name f1.2 lenses are just pretending to be fast, but losing light due to cheapo lens coating or whatever.
The only advantage of the 55mm is the slightly larger focal length. This is visible in the photos.
Just for the record I repeated the test with the Voigtlander Nokton 58/1.4, which gave the same result.
Btw. the contrast of the Nokton is significantly better. Sharpness is excellent of all three lenses. No softness here.
It might be interesting to compare the Pentax A50/1.2 to the 50/1.4. Is it really 1/2 stop brighter?
Nevertheless I will keep the Revuenon because it is very nice mechanically.
EDIT:
Second test must follow, if one can see a difference in DoF.
Will try tomorrow.
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Forum: Lens Clubs
10-02-2010, 12:36 AM
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It will depend on the outcome of my tests.
If there is really any advantage compared to f1.4 I will keep it.
But I am sceptical.
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Forum: Lens Clubs
10-01-2010, 12:53 PM
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Right.
f1.4 should be enough for anybody.
I am only checking this out to confirm that the above is right.
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Forum: Lens Clubs
10-01-2010, 10:04 AM
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Today I went with a friend to a lokal shop to get him a 55/1.2.
For some reason they had two of them, they were not expensive (from todays perspective, 85 €) and so I am a happy owner of this species, too, now.
It is like new:
first shot:
f1.2, 1/100 s, ISO 125
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