[Stavri]

Nicolas is very systematic in his approach, I always pay attention to his posts. That said when rating a lens, its important to include its price in the criteria. This is why the M 50mm f1.7 with an average value of $41.29 has a rating of 9.36 on pentaxforums. The Da* 55 with an average value of $676 has a rating of 9.18, while the DA 50mm f1.8 (valued at 175) has a rating of 9.28. This doesn't mean that the M 50mm f1.7 outperforms all these other lenses, but it's it's performance/cost ratio is higher.
The FA 50mm f1.4 is less than half the price of the DA* 55 and the FA 43. If budget is not an issue then clearly the DA* or the FA 43 would be the obvious choices. But are these lenses twice as good as the FA 50mm f1.4 (assuming you have a good copy)?

This is my rating:
F1.7 or slower with AF:
DA 50mm f1.8 is the winner. (I prefer the -F/FA 50mm f1.7 personally but the DA 50mm f1.8 can be had for around $100 used (compared to 140-175 for the -F/FA) You could always spent a bit more for built quality though.

F1.4 or slower with AF:
-F/Fa 50mm f1.4 is the winner, does 97% of what DA* 55 can accomplish with less than half the cost.

Premium Category:
-FA 43

A small quiz for you all: Find the lens:
-F 50mm 1.4 vs DA* 55mm f1.4 shot @ f1.6 (similarly compressed image, no PP) shot on the same couch inches and minutes apart.
Pic 1


Pic 2

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Last edited by Stavri; 03-17-2015 at 12:39 PM.

[6BQ5]

I'll play.

Pic 1 is the DA* 55mm f/1.4.

Pic 2 is the F 50mm f/1.4.

The hard parts i that the cat moved and is in two different positions. I am guessing due to the rendering of the whiskers.

[Stavri]

I'll play.

Pic 1 is the DA* 55mm f/1.4.

Pic 2 is the F 50mm f/1.4.

The hard parts i that the cat moved and is in two different positions. I am guessing due to the rendering of the whiskers.

True but we're looking for character as well as optical excellence. The DA* 55 is knowing for it's IQ and contrast at large apertures, I pitted it against the -F 50mm who's known for the opposite.

I'll take a few guesses before I disclose the info....anybody else?

[Nicolas06]

I honestly prefer the second, but for me the focus and apperture is key here:
- the first one the focus is bit behind the eyes and nothing really sharp. But particulary the front noze is out of focus and it show. I don't like it. There the very visible purple frigging on the first one on the whiskers. There also bokeh frigging on the fabric behind that doesn't help.
- the second one I think the head orientation of the cat compensate the very thin deph of field. The picture isn't that sharp, but there enough so the cat doesn't appear blurry. The different subject distance and bit different light avoided to have the purple frigging on the whiskers. The back of the cat that do not render so well on the first is hidden in the second one.

All in all the second photo is a better photo for me, both technically from maybe the gear point of view but also a lot from composition. And finally it just avoid the issues the first photo has. Maybe not because the lense is better but because the photo is different and so doesn't show the same scene.

Difficult to conclude for me but I know the issues on the first photos is issue I have seen on many on my FA50 photos and that the FA77 can also have too. I can't garantee DA*55 totally remove that, in particular as such wide apperture but that a rendering a DA70, DA35 or DA40 would never produce, for sure.

So let say first FA50, second DA*55, just so Stavri can say I was wrong... I know that the difficult cases are not present in second photos making it easier but let's decide...

[Stavri]

I honestly prefer the second, but for me the focus and apperture is key here:
- the first one the focus is bit behind the eyes and nothing really sharp. But particulary the front noze is out of focus and it show. I don't like it. There the very visible purple frigging on the first one on the whiskers. There also bokeh frigging on the fabric behind that doesn't help.
- the second one I think the head orientation of the cat compensate the very thin deph of field. The picture isn't that sharp, but there enough so the cat doesn't appear blurry. The different subject distance and bit different light avoided to have the purple frigging on the whiskers. The back of the cat that do not render so well on the first is hidden in the second one.

All in all the second photo is a better photo for me, both technically from maybe the gear point of view but also a lot from composition. And finally it just avoid the issues the first photo has. Maybe not because the lense is better but because the photo is different and so doesn't show the same scene.

Difficult to conclude for me but I know the issues on the first photos is issue I have seen on many on my FA50 photos and that the FA77 can also have too. I can't garantee DA*55 totally remove that, in particular as such wide aperture but that a rendering a DA70, DA35 or DA40 would never produce, for sure.

So let say first FA50, second DA*55, just so Stavri can say I was wrong... I know that the difficult cases are not present in second photos making it easier but let's decide...

It's -F 50 vs DA* 55 and I'll resist the temptation for now...

[Nicolas06]

Nicolas06,

Wow, that a very thorough analysis! It looks like you have thought long and hard about your lenses and I appreciate that. I have done the same and I ended up with the 31mm, 43mm, 50mm, and 77mm primes. We all shoot different subjects in different conditions with different styles. Of course, our lens selections will be different. Diversity in this case is a good thing. Imagine if everyone used the same lens. How interesting would that be?

Yeah and is not the FA50 f/1.4 is bad. It is just not as good as many other. Utimately, my eye sight is not good enough to allow accurate manual focussing through the OVF, and the FA50 f/1.4 focussing is not great.

I also think the f/1.4 apperture is far from being that interresting on this lense as a bit too weak to be that often usefull. I tend to think then that DA50 f/1.8 or FA50 f/1.7 are all in all better buy for entry level and that for high end all other prime in the range are better.

[Stavri]

Yeah and is not the FA50 f/1.4 is bad. It is just not as good as many other. Utimately, my eye sight is not good enough to allow accurate manual focussing through the OVF, and the FA50 f/1.4 focussing is not great.

I also think the f/1.4 apperture is far from being that interresting on this lense as a bit too weak to be that often usefull. I tend to think then that DA50 f/1.8 or FA50 f/1.7 are all in all better buy for entry level and that for high end all other prime in the range are better.

You eyesight looks excellent to me from your analysis. I agree with you that my comparison is flawed, The DA* 55 when shot expertly can deliver images that -F/FA could never do. The purpose of my quick and dirty showdown was to reevaluate the F/FA capabilities at wide apertures, and make us think long and hard before dismissing it from our discussion as an inferior product.

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Last edited by Stavri; 03-17-2015 at 01:40 PM.

[Sandy Hancock]

The top image has much more longitudinal CA. I would guess it is the F50

[Nicolas06]

You eyesight looks excellent to me from your analysis. I agree with you that my comparison is flawed, The DA* 55 when shot expertly can deliver images that -F/FA could never do. The purpose of my quick and dirty showdown was to reevaluate the F/FA capabilities at wide apertures, and make us think long and hard before dismissing it from our discussion as an inferior product.

Let say that it is difficult to use at wide apperture (up to f/2) because then it has:
- low contrast
- unreliable phase detect AF in particular on bodies like K5 or older. Need live view or manual focus to get just right...
- not that sharp.
- show quite some visible aberations.

With good light on right subject like portraiture it will work and give quite pleasing results in particular allowing to get a pleasing soft rendering when you need it with a lot of blur in the background. On the opposite, it provide really sharo, colorfull and contrasty results closed down to f/4 or more.

I'am not sure it distinguish itself that much then against 50 f/1.7 and f/1.8 lenses that have only 1/2 stop less of light gathering and the associated 20% more deph of field. And theses lenses are typically cheaper. The DA50 has digital coating helping it a bit.

I invested in it instead of cheaper DA50 f/1.8 or FA50 f/.7 back in time and I think it was not worth the trouble.

If you have time and cooperating subject, this kind of lense let you try wide apperture for low price and get interresting shoots.

Higher end lenses tend to get more center sharpness at wide appertures, more contrast/micro contrast, more reliable AF and better rendering overall. It will not show on all photos depending of the lense, and it is for everybody to think of the price depending of his needs.

There anothing too to consider... Even DA*55 is maybe more for f/2 and more closed down as is obviously by their parameters FA77, FA43, DA70...

If really, really you want ultimate f/1.4 performance, I think this is more FA*85 f/1.4, sigma/samyang 50 or 85 f/1.4... But theses things are huge. That a reason for me to not get them... in addition for me to think f/2 is enough in most situations on APSC (but f/2.8 a bit limiting).

[drypenn]

The FA50 has certain qualities that makes it unique. It renders contrast in a very film-like manner. The DA*55 has a more perfect rendition (save for that CA), but there's no denying that it looks too digital for me.

[Stavri]

The FA50 has certain qualities that makes it unique. It renders contrast in a very film-like manner. The DA*55 has a more perfect rendition (save for that CA), but there's no denying that it looks too digital for me.

Which is which sir?

[drypenn]

Which is which sir?

Top is F50, bottom is DA

[Stavri]

Top is F50, bottom is DA

Is that you final answer (would you like to phone a friend?)

---------- Post added 03-17-15 at 08:30 PM ----------

Before I reveal the answers I want to let you all know that this particular image from the DA* 55 was intentionally shot haphazardly to match the -F 50mm f1.4. The DA* 55 f1.4 when shot expertly produces images that cannot be matched in terms of IQ and micro-contrast especially at large apertures. Before you dismiss my copy as defective I'd like to state that my DA* 55 just but equals the sharpness of the excellent Sigma EX 50mm f1.4 I let go a few months ago. Most people where throw off by the CA on the whiskers erroneously attributing it to the -F (the DA* 55 under certain conditions also exhibits CA at large apertures) When viewed carefully the DA* 55 focused behind the eyes exhibits slightly better sharpness and micro contrast.

DA* 55 @ f1.6


-F 50mm @f1.6

[Stavri]

DA* 55 vs Sigma Ex 50mm f1.4 both shot at F1.8 (note: profile read Ex 70-200mm f2.8 erroneously), my copy of EX 50 1.4 was really sharp (the current owner has also confirmed it to me) and the DA* 55 kept up with the Sigma exhibiting better micro-contrast and blacks

Da* 55 @ f1.8

Crop:

Sigma Ex 50mm f1.4

Crop:

[Stavri]

(sorry for the double posting, I thought it relevant to our discussion)

The -F 50mm f1.4 needed some AF adjustment today, (-4), I put it against the DA* 55 one more time (shot from 15" away, this time both lenses shot wide open)

Had set the aperture to Auto, the DA* 55 shot at 1/30 the -F 50 shot at 1/50. It seems the older FF is brighter.

DA* 55 @ f1.4


-F 50 @ f1.4


crops: