Visit MPB Visit MPB Visit MPB

Pentax-FA 50mm F1.4 v Pentax-A 50mm F1.7 @F2

iceblinker
Posted 02/02/2010 - 14:34 Link
I thought I'd post this in case it's of any interest to anyone deciding between these two lenses.

I've chosen to compare at f2 because that's when the FA begins to have a decent level of sharpness (in my opinion), and this aperture may be used when you want a significant speed advantage over a more ordinary lens.

The following results are consistent with other tests I've done. I made several attempts at focus with each lens and chose the sharpest results. It's possible that I could have focused more accurately still, but only a tiny bit, if at all.

Handheld, but shutter fast enough to freeze any camera shake (1/400 and 1/250 sec, respectively). SR on. ISO 100. RAW + Silkypix, same settings for each image.

Uncropped:
Pentax-A 50mm F1.7 @ F2:
Comment Image


Pentax-FA 50mm F1.4 @ F2:
Comment Image


100% crops:
Near centre:
Pentax-A 50mm F1.7 @ F2:
Comment Image


Pentax-FA 50mm F1.4 @ F2:
Comment Image


Border:
Pentax-A 50mm F1.7 @ F2:
Comment Image


Pentax-FA 50mm F1.4 @ F2:
Comment Image
~Pete
Edited by iceblinker: 02/02/2010 - 14:45
womble
Posted 02/02/2010 - 14:50 Link
To my eyes the 1.4 has the edge. K.
Kris Lockyear
It is an illusion that photos are made with the camera… they are made with the eye, heart and head. Henri Cartier-Bresson
Lots of film bodies, a couple of digital ones, too many lenses (mainly older glass) and a Horseman LE 5x4.

My website
Greytop
Posted 02/02/2010 - 14:50 Link
Interesting Pete, thanks for posting.
I do like my little FA 50 f/1.4
Regards Huw

flickr
beginner
Posted 02/02/2010 - 15:22 Link
Yup! the 1.4 gets my vote!......but could it be down to manual focussing!.....my 1.7 is extremley sharp when I get it spot on......Ken
K20D...ist DS ,DA18/55,DA16/45.DA* 50/135,"A"1.7 50MM..."A" 70/210..M 50mm f2...Tamron 90mm macro,28/300 Tamron,200/500 Tamron 6.9....A Pentax DA*300... Sigma10/20,FA31mm 1.8 Ltd*********,FA 77mm Ltd!
Edited by beginner: 02/02/2010 - 15:22
robbie_d
Posted 02/02/2010 - 15:26 Link
1.4 wins it for me.
If you can't say something nice about Pentax, you won't say anything at all.

Apparently.
Adqam
Posted 02/02/2010 - 16:14 Link
I see that you are comparing the A 1.7 with the FA 1.4. You might like to check out this link:

http://www.pentaxforums.com/forums/pentax-slr-lens-discussion/81528-fa50mm-f1-4-...

Where a FA 1.7 is compared to the FA 1.4. I had thought that the A and FA lenses were optically identical? Indeed, Dimitrov's website seems to indicate that this is the case.
iceblinker
Posted 02/02/2010 - 16:22 Link
beginner wrote:
Yup! the 1.4 gets my vote!......but could it be down to manual focussing!.....my 1.7 is extremley sharp when I get it spot on......Ken

My manual focusing perhaps could have been a touch better, but I did try about 8 times with this subject. Started at infinity, take a shot, move the ring a tiny bit, take another shot, and so on. Then I chose the sharpest. Out in the real world, I'm unlikely to often focus it better than this (despite having a Katz Eye screen).

Also with other subjects, no matter what I do, I can't get the 1.7 lens quite as sharp as the 1.4 at f2. It's pretty good, yes, but not quite as sharp and contrasty.

I was wondering which of these two lenses to take next time I go on holiday. The 1.7 is lighter and would be Łess to Łoose, but the 1.4 does seem better at f2 - which is a setting I really would use. For smaller apertures, I tend to stick with my zooms for convenience.
~Pete
johnriley
Posted 02/02/2010 - 16:26 Link
On the face of it, as there really isn't much difference in bulk, why not take the f1.4? You could also get a good price on eBay for the A lens.

The only caveat I would have for interpreting the results from this test (apart from preferring tripod mounted shots and no SR to remove those two variables) would be that we are only comparing one example of each lens. These could be typical or not, but we have no way of knowing.

We only really know a lens after regular use unless we are in the optical lab, and the nicest Pentax 50mm I have every had was actually a SMC Pentax-M 50mm f1.7 - perhaps it was a really good example of its type.
Best regards, John
iceblinker
Posted 02/02/2010 - 16:31 Link
Adqam wrote:
I see that you are comparing the A 1.7 with the FA 1.4. You might like to check out this link:

http://www.pentaxforums.com/forums/pentax-slr-lens-discussion/81528-fa50mm-f1-4-...

Where a FA 1.7 is compared to the FA 1.4. I had thought that the A and FA lenses were optically identical? Indeed, Dimitrov's website seems to indicate that this is the case.

It's interesting that the test there shows the opposite to what I found. I don't know if that's due to focusing problems (with me or them) or sample variation with the lenses.

All I can say is that I've tried very hard to get as good results with my 1.7 as my 1.4 at f2, and have failed. The 1.7 lens looks to be in good condition, and I'm the only owner. (Got it back in 1984 with a P30).
~Pete
Edited by iceblinker: 02/02/2010 - 16:39
iceblinker
Posted 02/02/2010 - 16:38 Link
johnriley wrote:
The only caveat I would have for interpreting the results from this test (apart from preferring tripod mounted shots and no SR to remove those two variables) would be that we are only comparing one example of each lens. These could be typical or not, but we have no way of knowing.

Agreed, and it's possible that my 1.7 is substandard.

Tripod test are preferable, but I'm confident that those varables are not playing a part as the results have been consistent over many shots.
~Pete
thoughton
Posted 04/02/2010 - 14:07 Link
The 1.4 seems better. However your A1.7 shots at f2 seem a fair bit less sharp than my A1.7 @ 1.7.

On an unrelated note, your FA results are considerably superior to my old Super Takumar 50mm 1.4 at f2, and are still a little better that the Tak at f2.8.
Tim
AF - Pentax K5, Sigma 10-20/4-5.6, Tamron 17-50/2.8, Sigma 30/1.4, Sigma 70-200/2.8, Tamron 70-300/4-5.6
MF - Vivitar CF 28/2.8, Tamron AD2 90/2.5, MTO 1000/11
Stuff - Metz 58 AF1, Cactus v4, Nikon SB24, Raynox 150, Sigma 1.4x TC, Sigma 2x TC, Kenko 2x macro TC, Redsnapper 283 tripod, iMac 27”, Macbook Pro 17”, iPad, iPhone 3G
FlickrFluidrPPGStreetPortfolio site
Feel free to edit any of my posted photos! If I post a photo for critique, I want brutal honesty. If you don't like it, please say so and tell me why!
iceblinker
Posted 05/02/2010 - 09:33 Link
Sorry, I made a mistake with the cropping above. The original crops were 620x620 pixels. They got accidentally resized to 775x600.
~Pete
Mongoose
Posted 05/02/2010 - 10:04 Link
thoughton wrote:
On an unrelated note, your FA results are considerably superior to my old Super Takumar 50mm 1.4 at f2, and are still a little better that the Tak at f2.8.

There was an optical re-design of the 50mm between the M and A series, so A, F and FA 50's should be better than M, K, and Super Taks in this case. I believe this is supposed to be most obviously true of the 1.4s.
you don't have to be mad to post here



but it does help
iceblinker
Posted 05/02/2010 - 14:38 Link
After much MF effort, I have now managed to get a sharper shot of the same scene from my 1.7 than above at f2. I now reckon it's pretty close to the 1.4.

I'm sorry my test above was somewhat misleading. I won't bore you with more images unless I do a more scientfic test.
~Pete
SteveA
Posted 08/02/2010 - 20:40 Link
Have you tried catch in focus? Press the shutter release down & slowly rotate the focus ring - the camera fires the shutter when in focus?

Add Comment

To leave a comment - Log in to Pentax User or create a new account.