[audiobomber]

I don't think the hood is the main problem, Look the M 50 1.7 - front element is very well exposed to light but does it have problems - I don't think so . It is just that this old planar design is not that good wide open and that's it...

How does your M50 1.7 do at F1.4? It is pretty universally accepted that the f1.7 has slightly higher contrast at apertures below f/2.8. It is also pretty universally accepted that the f/1.4 has better bokeh due to more blades. You can add contrast, but you can't improve bokeh.

This is the test I mentioned above showing the effect of a hood, originally conducted and posted by dgaies:

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/81528-fa50mm-f...tml#post829168

Uncropped scene:

The FA 50 sharpens up a lot at 2.8, but it is useable wide open. I shot this flower @ f1.4:

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Last edited by audiobomber; 09-07-2012 at 09:53 AM.

[simbon4o]

Sorry, have to disagree. All the comparisons are clear that a hood makes a big difference. As for the design.....

My point was that without hood the 1.7 is better and it's front element is not hidden, so maybe the problem of the 1.4 is coatings or something else.
I have both and a good hood with some broken UV filters(to extend it) and the results are clear - FA 50 1.4 is awful wide open, not only soft and low contrast, it has the most awful bokeh in most situations I have seen from pentax lens. It is so distracting and harsh. Everything changes when closed down to 2.2 and even more, but wide open the M 50 1.7 is way better, even for low light shooting the 1.4 is not my choice. Closed down if we are not looking for bokeh(for example landscape or macro or...) the M 50 1.7 is better again being sharper with almost none CAs.

How does your M50 1.7 do at F1.4? It is pretty universally accepted that the f1.7 has slightly higher contrast at apertures below f/2.8. It is also pretty universally accepted that the f/1.4 has better bokeh due to more blades. You can add contrast, but you can't improve bokeh.
...
The FA 50 sharpens up a lot at 2.8, but it is useable wide open. I shot this flower @ f1.4:

So I will repeat myself - I have both I can't open the M 50 1.7 to 1.4, but the 1.4 is not usable at 1.4 as I want to so... I don't use it wide open therefore it doesn't matter. If we look globally there are only a few 1.4 50s which are nice and usable at 1.4(this is my opinion of course!) and one of them is the summilux 50 1.4, other is Sigma 50 1.4, I can't think of another one right now but... maybe I miss something. The thing is - not everything is sharpness, contrast and fast aperture, look at the canon 50 1.2L - awful performance wide open. The pentax 50 1.4 makes no difference it suffers from the same problems that suffers all other planar designed lenses like it - canon(the actual model), nikon(older model), sony(current model), zeiss 50 1.4 which has 7 elements in 6 groups. Newly developed designs are better but not cheap .


PS about bokeh and 50s - we are shooting with APS-C sensors so the 50mm is a portrait lens. That's why I dont like the FA 50 1.4 at 1.4 - it is almost impossible to take a portrait wide open with nice smooth OOF/bokeh/... the good thing is that this planar design makes nicer results closed down so for me it is a nice AF 50mm 2.2 lens . The same thing is with the DA*55 1.4 - nervous render wide open.