[Docrwm]

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I've ever compared all my M and A 50's. (2.0, 1.7, 1.4)
With a deep hood, I wound that they were all pretty similar in sharpness.
The 50/1.7 is a good deal price/speed/performance wise, but its lack of aperture blades does show in the bokeh every now and then (Hexagonal OOF highlights) and bokeh itself isn't as good as the f1.4.

It really comes down to personal preference but I find the FA50/1.4 with a hood is really the best of all worlds with great bokeh, good colors, excellent IQ at most apertures, and autofocus to boot. I'll be interested in seeing what the 50/1.8 that is coming out soon sells for and how the images look that come from it.

[monochrome]

I'm in the "How many 50's is too many 50's" evolution of LBA right now. However many too many is it is very many more than I have.

The ubiquitous on eBay Takumar 135/3.5 screw-in metal hood works well for the M50/1.7 on APSc format, but would likely vignette on 135. I keep one around for a really bright day with my 50's. Otherwise I just use the traditional plastic clip-on and no filters.

The 1.7/1.8 Pentax 50's of all the m42 and K-mount have an optical formula optimized for a flat field (sharp corner to corner) with a neutral cast. The 1.4's are optimized for background blur (I hate that other B word) which helps to promote 3-dimensionality in your subject, but at wide apertures the 50's can be soft in the corners. Therefore you should definitely keep both lenses!!

Mine are almost identically sharp above 5.6. The optical formula of the 1.4's is supposed to have been unchanged for years until the A50/1.4, when it was reportedly tweaked for sharpness. The FA has the same optical formula as the A. Aside from that the changes over time were only to the coating formula. Your color cast changes between the M50/1.7 and FA50/1.4 might be the result of these coatings changes, making the FA a bit cooler - but giving beautiful sky hues (with hoods ).

If you've never visited Boz's K-Mount page, compare your lenses at this link.

[timo]

I have the FA50 f/1.7, the M50 f/1.7, and the M50 f/1.4. I used to have the FA50 f/1.4, but sold it. For landscapes, say, I think the 1.4s are better at the edges. Wide open, many people say the 1.4 (either version) is not as sharp as the 1.7 but I've never been totally convinced about this - as with the 1.2, it is really hard to get the focus spot-on with the 1.4, and also there seems to me a loss of contrast rather than a lack of sharpness. For wide-open use I prefer either of the manual versions to the FAs, because you can control the focus more easily, especially with LV. As others have said, the bokeh of the 1.4s is a bit nicer (although the 1.7 is still pretty good). Having been round this particular track, I feel that whatever you have stick with it - they all perform well, and the differences are very subtle.

[Ikarus]

The site doesn't say, could you tell me - how deep is that hood?

It's a straight tube, 35mm long, 58mm diameter. The one I linked to looks like the one I got, but I'm not 100% sure, since the dimensions are missing (as you noticed). As already mentioned, this hood does not vignette with a 35mm on APS-C, so it's a safe bet that it is not optimal for longer lenses. I've been looking for deeper hoods of the same narrow width for my 50s and the Jupiter-9 85mm, but unsuccessfully so far.

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Last edited by Ikarus; 03-30-2012 at 08:37 PM.

[twitch]

That one looks too short for a 50mm on APS-C. I have one of these and it doesn't even vignette with the DA 35/2.4.

I use my fa50 on film 90% of the time.....

[Schmidlapper]

I did a comparison awhile ago of several 50s linked below, including examples of my A50/1.7, M50/1.7 and M50/1.4 (no FA50s), It does support what monochrome wrote regarding optimization of sharpness of 1.7 1.8 over 1.4 wide open. I always like to point out it is a small sampling and my results are not representative of every lens made, rather just another data point for debate here.

I have placed on Flickr a fairly well controlled comparison of my various normal lens choices, to include A50/1.7, M50/1.4, M50/1.7, SMC Tak 55/1.8, Tamron 17-50/2.8 and a DA55-300/4. The samples shared are for wide open, f5.6 and f8 for center resolution. Corner resolution did not change order of sharpness nor appear out of line. This was only a one lens sampling, but may be interesting, and it helped me change my own usage decisions. I now use my M50/1.7 over my M50/1.4 as my take along bag normal as it was the sharpest of the lot, for pTTL flash portraits I use the A50/1.7 as it was a close second . I had thought my 55/1.8 was not focusing correctly prior to this test based on some photos, but it came in third overall in my opinion in this test. To round out the manuals the M50/1.4 came in fourth for wide open resolution in my view. The link is Collection: My Pentax 50mm normal resolution comparison test and gives the general parameters of my method of testing. I am not picking on anyone else's pet lens but I feel this would be a worthwhile method for anyone who has multiples and variations to determine which is their sharpest. Let me know if this is helpful information on here?

[Jonathan Mac]

I have nine different 50 or 55mm lenses, and the M 50 1.7 is my favourite, mostly because of the fantastic colours it produces. As it's a good protrait length on APS-C, a warmer tone is very beneficial.