Great comments, very interesting opinions...
Quote: Some say the 50 f/2 is really the same optically as the 1.7 but it's just restricted to f/2. There was a thread here a few weeks ago about that.
This surfaces from time to time. It's not true. The optics are different, and I can testify that the performances are different. The F 1,7 is much shrper than the M f2.
Quote: The FA50 1.4 you get a trade off between the speed and softness wide-open. But stop down the lens and you get as sharp an image from the lens as any other in the right conditions.
Correct. I am not shopping for a lens right now, the F50 1,7 is perfect for me. I am just curious about the opinions of others, since many people (me among them) think the 50s f1,4 are not excellent wide open.
Quote: You need to take into account the prupose of the fast aperture, you either need it for an extremely shallow DOF, (and I really think, that many complaints about poor contrast can be traced back to not correctly focused images at such a shallow DOF) or because the light is extremely poor. In that condition, lack of contrast is simply a none-issue, as a slower lens wouldn't get you the shot.
That is correct, in theory, but even them I could never convince myself to use my A f1,4 wide open. That's why I went for the F f1,7, since I find it better than the 1,4 at f1,7 (or 1,8 in the case of the A).
Quote: whoever thinks the FA50 is bad at 1.4 is wrong.
Never said it was bad. I said that it's celarly not as good as closed down
Quote: At f2 in low light, autofocus is not working at all
A wider lens helps for this, more light helps the AF system.
Quote: For those of you who own a FA 50 f1.7, how sharp are the pictures, when stopped up, for general purpose photography, such as street action, group shots, running children/pets, action shots, etc?
closed down it is impossible to decide which is the sharpest, my F 50 f1,7 or my FA 50 f2,8 macro. The latter is reknowed as one of the sharpest lenses ever made, ever. To my eyes they look similar stopped down. At f2,8 the macro is better, at f4 and beyond there is no difference. But I rarely use my 50 f1,7 when light levels are not very low.
Quote: What sort of subjects are you going to be shooting in low light?
For me it's mainly city walks, nature walks, that sort of things. When doing low light photogrpahy I either bring my tripod, my f1,7, or both, depending on the situation.
Quote: shifting the focus by even 1mm will make a huge difference in sharpness at F1.8
Absolutely correct, that's one reason why I like the F1,7, too. Its AF system is so reliable, I cannot do better by focusing manually, even with live view magnification on a tripod.
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I'm a bit surprised (but I guess I shouldn't be) that so many people use the FA35 in low light. It's a very good compromise indeed. Thanks for the input, everyone, it makes an interesting read.