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05-09-2008, 10:32 PM - 1 Like   #1
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Pentax A 50mm 1.2 - Long Discussion and Photos

I wanted to outline my brief experience with the A50 1.2 and present some discussion as well as a centralized location for the excellent resources at hand.

Coles Notes Version
The A50 1.2 is a great lens but terrible value unless you really need the light!

If you want to hear my long winded babbling, here it goes
The K100D is my SLR and admittedly I don't really know what I'm doing besides what I learn from valuable resources on the internet (especially this forum) and my experience is only from taking vacation photos. But I love gadgets and finely crafted metal objects which is why I've put money into a set of FA Limiteds and hoping in time I will learn to appreciate the finer qualities.

I picked up an M50 1.4 off this forum as my Fast Fifty and I thought it would be sufficient. It is small, well constructed out of metal and has a very smooth focus ring. What kind of bugged me was stop down metering. It is tolerable when you have the time but not if you need to get a shot. It constantly underexposed and the the inability to use it with the flash was a downer. I sought to find alternatives with similar properties but with the "A" feature. Basically there is the Voigtlander Nokton 58mm 1.4, Zeiss ZK 50mm 1.4, Pentax A 50mms.

What drew me to the A50 1.2 was
1. The A50 1.2 is very highly regarded in many tests
a. Eric Tastad's Test
LBA: A50mm f1.2 vs FA 50mm 1.4: Pentax SLR Talk Forum: Digital Photography Review
b. Sean Carpenter's Normal Shootout
the Normal Lens Shootout Photo Gallery by Sean Carpenter at pbase.com
c. Jim King's Test
Comparison of Pentax Fast 50s [Page 1]: Pentax SLR Talk Forum: Digital Photography Review
d. Sample photos and Cogitech's reference to a German review showing it is the best super fast 50 of any brand
Manual Focus Forum / Pentax K 50mm f1.2 and K 85mm f1.8 shot wide open
2. The sheer speed!
3. Bragging rights :P (at least i'm honest)
4. Pentax now in their more conservative state of mind will probably not produce fancy lenses like these because it would not be worth the resources necessary to produce this lens. (Can you imagine any gold Pentaxes now? Not bloody likely)
5. The many discussions on this forum about this lens

After seeing Volosong's post https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/26441-lba-firs...-50-1-2-a.html (excellent unpacking photos), I finally caved. I purchased the same thing from Matsuiyastore on eBay. Note that Matsuiyastore has excellent excellent service. I won on a Buy It Now and was messaged the next minute. Shipping was faster than items I had received from the States and he marked it as a gift and marked down the value. They also have many rare Pentax items for sale at reasonable prices.

Build Quality
I had received the FA Limiteds a few days prior and I can say that it is almost equal in quality. The heftier weight balances well with the K100D, more so than the M50 which seems a bit too small. The lens feels like it is entirely made of metal, whether or not this is true is hard to tell. The aperture ring kind of feels like plastic but it has the coldness of metal, but not as convincing as the FA Limiteds. The grip is different from that on the M series lenses and digs into my fingers more, I like it a lot. The focus ring is smooth without the stronger resistance of my M50 1.4 and I do like it better; not Takumar good, but very good. However, when I bought an FA35 I got a nice pouch, proper lens caps and a hood. For this lens there are no goodies and the same crappy "plugin" rear cap like the kit lens.

Usage
It is beyond difficult to focus at 1.2 and i'm starting to notice the limitations of the Pentaprism finder. The M50 1.4 was much easier to focus. The difficulty in getting accurate focus in 1.2 degrades the wide open feature slightly. It is kind of like a game to see which photo comes out the sharpest and to see which part was actually in focus. That's ok for me because I'm the kind of person who chimps every shot at maximum magnification to check sharpness. With all my Manual Focus lenses, I find the Focus Indicator serves more as a hindrance than help. (edit: actually using the FI and seeing it sharp on the focus screen is usually good). A focus screen would probably help a lot. In terms of exposure, I noticed that in Aperture Priority with Auto ISO, when opening up the aperture to wide open, the lens may bump down the ISO which leads to some irregular overexposure. It is probably best to set the ISO first.

Image Quality
Honestly from my n00b eyes, I don't think it takes pictures demonstrably better than the M50 1.4, however the extra half stop is handy and is fun to play with. James Wei (Roentarre) does have some very positive remarks about its bokeh. When focused correctly, the 1.2 is fairly sharp, however getting the focus is tough.

Value
This lens before shipping cost $579 USD, after all fees, cost $640 CDN. An A50 1.4 can be had for around $150 and an FA50 1.4 can be had for $200. Even the Voigtlander Nokton 58mm at $379 is relatively good value or Zeiss ZK 50mm 1.4 at $550 is cheaper. This is brutal value for an extra half stop of light, but if you need it, there are no "A" substitutes for Pentax.

Non "A" Alternatives
1. Pentax 50 1.2 said to be sharper in the corners.
2. Revuenon 55mm 1.2 in M42 or K-mount which was available for cheap but not anymore, but technically, probably not as good as the Pentax. One of the posters below had good experiences. Also the similar Cosina version for K-mount
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/38754-cosina-curiosity.html

Conclusion
Will I be selling it anytime soon? HELL NO!

Addendum
sad to say after a few months, early August i did end up selling the lens. nothing to do with the quality of the lens. but first of all the 1.2 aperture is hard to use and requires focus bracketing that i wasn't prepared to do. the pictures at 1.2 can be great, but i couldn't find situations where i would use it. as well the lens is kind of heavy and does not balance well on the K100D (in fact most lenses don't balance well on the K100D). and couldn't find a heliopan 52mm hood to go with it like Frank did . for me DOF cravings now i turn to my FA77

PentaxForums resources
PentaxForums K50 1.2 user reviews, the K is similar in construction.
Pentax Lens Review Database - 50mm F1.2
PentaxForums A50 1.2 user reviews, Lance B liked it so much, he posted multiple times!
Pentax Lens Review Database - 50mm F1.2
More forum discussions
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/24710-not-thrifty-fifties.html
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/25781-k-50mm-f1-2-a.html
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/18852-estate-s...ns-before.html
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/24777-pentax-50mm-f-1-2-a.html
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/22730-picked-u...0mm-1-2-a.html
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/12405-smc-50-1-2-a.html
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/24643-wich-50m...d-you-buy.html
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/27293-lba-pent...m-1-1-2-a.html

Non PentaxForums resources
Stan's Photography compiled from the posters on PDML. This is probably where the "soft" reputation of the lens came from, however the tests above show this to be false.
Brief Comments
Lens Diagrams, the 50 1.2 is similar to the 50 1.4.
Pentax M & A Lenses

My photos taken at f1.2:
I tried to take some photos around the house that would show the super narrow DOF and then some in very dark spots (spot metered) to show light gathering capability. There is no real need to show more stopped down pictures because it will be close to the other Fast Fifties, in otherwords, very very good.
Pictures were taken RAW and quickly converted using Irfanview, NO PP.
1. The top of Jesus's head is in focus and the body is not, see the 100%.
2. ISO 3200 1/15 maximum light gathering for my K100D.
3. ISO 1600 1/8 outdoor street light only.
4. ISO 200 testing sharpness. I focused a few to choose the best, see the 100%. The focus point appears to be on the word Cognac, but above the word is slightly blurry due to the curvature of the box.
5. A fun shot of my Guitar Hero guitar with some PS2 games in the back, focused on the front of the orange key.












Last edited by k100d; 10-09-2008 at 08:47 AM.
05-09-2008, 10:32 PM   #2
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100% crops
1. Focused on the word Cognac, acceptably sharp, grrrr purple fringing
2. Focused on the head




Last edited by k100d; 05-14-2008 at 06:48 PM.
05-09-2008, 10:46 PM   #3
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Any remarks would be most welcome. I'd be happy to conduct any tests as well.
Thanks for looking

Last edited by k100d; 05-10-2008 at 10:08 AM.
05-09-2008, 11:47 PM   #4
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A very nice discussion - it's not long, though, which is good. (Long would mean going into physics-professor territory and start discussing the optical formula.)

Also, can you please get a photobucket (not flickr, people steal your images) account?

Page widening gets kinda annoying. I'm on 1152 x 864, and I have to scroll all the way across.

I'm sorry, I don't mean to whinge.

Also, uploading pictures directly to the forum uses both precious forum bandwith and server space.

05-10-2008, 12:52 AM   #5
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A 50mm f1.2 is a very nice lens. But it is just so hard to use.

For candid, there is no time to manual focus while the pedestrians would give you a F word.

For night time photography, it is always too late to discover unsharp images after getting home.

For still life photography, f1.2 is just too thin for DOF that nothing is sharp except one point in the image.

The problem with bragging right is the fact that you would need images to brag about instead of a lens. Trying to churn out images with this lens is really a hard task. Creative lens for sure but just requiring a lot of creativity!
05-10-2008, 04:12 AM   #6
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Very thoughtful and (to me) accurate depiction of the 1.2s pluses and minuses. I have the 'K' and 'A' versions and find them equal in IQ and equally difficult to use wide open. I have found I get many more 'keepers' using them on the K20 than I did with the K100. In low light the extra stop is very valuable to me.......and then as you say........bragging rights......
05-10-2008, 06:35 AM   #7
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Very interesting thread to say the least and I really apreciated the thinking and effort in testing. I was contemplating buying a K50 f1.2 but it is not a priority right now. It is very disappointing that there are no new designs (Pentax or third party) for a modern f1.2 which will retain resolution and contrast acceptable from 1.2 on making it usable for very low light on modern DSLRs.

Radu
05-10-2008, 07:29 AM   #8
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As you know I have got the K50/1.2, yes focusing is hard i feel better with the split screen. When you got it focus, it actually show that it is quite sharp for print ( at least for me ) at wide open.
For $350 to get one of the fastest lens in Pentax line, it is worth it

I should try it in low light...



100%




Last edited by vizjerei; 05-10-2008 at 07:41 AM.
05-10-2008, 09:12 AM   #9
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QuoteOriginally posted by lithos Quote
Also, can you please get a photobucket (not flickr, people steal your images) account?

Page widening gets kinda annoying. I'm on 1152 x 864, and I have to scroll all the way across.

I'm sorry, I don't mean to whinge.

Also, uploading pictures directly to the forum uses both precious forum bandwith and server space.
funny, when i resize my window, i don't have a problem with page widening on my browser, the images aren't particularly wide (600 px max). and the photos are small in size so it shouldn't be a big problem. i don't really want to pay for a hosting site to be honest and i'd much rather support this forum instead. edit: i didn't realize Photobucket was free, i've changed the photos.

QuoteOriginally posted by roentarre Quote
A 50mm f1.2 is a very nice lens. But it is just so hard to use.

For candid, there is no time to manual focus while the pedestrians would give you a F word.

For night time photography, it is always too late to discover unsharp images after getting home.

For still life photography, f1.2 is just too thin for DOF that nothing is sharp except one point in the image.

The problem with bragging right is the fact that you would need images to brag about instead of a lens. Trying to churn out images with this lens is really a hard task. Creative lens for sure but just requiring a lot of creativity!
i think you've summed it up a lot better than i did! but the good thing is the lens works well in all the other aperture ranges as well. i think when anybody gets a very fast lens, the first instinct is to try to take as many photos wide open as possible but i'm trying to avoid that. after more thought, i'm not sure if i'd take on vacation with me, possibly too tedious.

QuoteOriginally posted by John Kovarik Quote
Very thoughtful and (to me) accurate depiction of the 1.2s pluses and minuses. I have the 'K' and 'A' versions and find them equal in IQ and equally difficult to use wide open. I have found I get many more 'keepers' using them on the K20 than I did with the K100. In low light the extra stop is very valuable to me.......and then as you say........bragging rights......
QuoteOriginally posted by RaduA Quote
Very interesting thread to say the least and I really apreciated the thinking and effort in testing. I was contemplating buying a K50 f1.2 but it is not a priority right now. It is very disappointing that there are no new designs (Pentax or third party) for a modern f1.2 which will retain resolution and contrast acceptable from 1.2 on making it usable for very low light on modern DSLRs.
thanks John and RaduA. i kind of want to make one post with links to all the resources that i've used and use as a reference for myself and other people interested in the lens.

with the higher quality of upper ISO levels, ultra fast lenses are more of a novelty. i think the most modern 1.2 is the Canon 50 which when used in careful hands can give nice results. there are rumours that Leica will release a <f1 limited edition Noctilux, so it will be interesting to see pictures coming out of that lens.

QuoteOriginally posted by vizjerei Quote
As you know I have got the K50/1.2, yes focusing is hard i feel better with the split screen. When you got it focus, it actually show that it is quite sharp for print ( at least for me ) at wide open.
For $350 to get one of the fastest lens in Pentax line, it is worth it
nice photos! i haven't taken any photos outside because i've been busy with other things. but your post also pushed me closer to getting the lens,
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/25781-k-50mm-f1-2-a.html i should consider a split screen, but don't really want to mess with the camera too much. i was getting good with the M50 1.4 so maybe with some practice i will be able to focus better

edit i also added a bunch of links to the original posting

Last edited by k100d; 05-10-2008 at 11:56 AM.
05-10-2008, 09:22 AM   #10
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i am looking for some fool that is selling one cheep ( yep i have a HOLE 20$ for them LOL) but in a M i think to make a set LOL i have the 1.7 and 1.4 (thow it would not nessarly HAVE to an M LOL)

then after that well Cannion makes a 50 F0.96 that would be cool to convert to a Pentax mount LOL

Last edited by nathancombs; 05-10-2008 at 09:28 AM.
05-10-2008, 11:55 AM   #11
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QuoteOriginally posted by nathancombs Quote
i am looking for some fool that is selling one cheep ( yep i have a HOLE 20$ for them LOL) but in a M i think to make a set LOL i have the 1.7 and 1.4 (thow it would not nessarly HAVE to an M LOL)

then after that well Cannion makes a 50 F0.96 that would be cool to convert to a Pentax mount LOL
just gotta get lucky and try to see if you can find a cheap local posting
with the $20 you can complete your M set with the M50 2.0

check out this post on the Canon https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/25680-who-has-...lens-dslr.html
05-10-2008, 04:24 PM   #12
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Hey K100D, did you went to HighPark this year for the Cherry Blossoms? A great place for a 1.2
05-10-2008, 07:57 PM   #13
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QuoteOriginally posted by vizjerei Quote
Hey K100D, did you went to HighPark this year for the Cherry Blossoms? A great place for a 1.2
really? didn't even know! all i know is it's big in Washington DC. i gotta start finding photo spots in Toronto once i have the time to shoot!
05-11-2008, 01:43 AM   #14
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QuoteOriginally posted by k100d Quote
funny, when i resize my window, i don't have a problem with page widening on my browser, the images aren't particularly wide (600 px max). and the photos are small in size so it shouldn't be a big problem. i don't really want to pay for a hosting site to be honest and i'd much rather support this forum instead. edit: i didn't realize Photobucket was free, i've changed the photos.
Cheers mate. Sorry if I came across as an a-hole. Photobucket's been good for me - when you signed up, did you put a "555" phone number in the "SMS" thing at the end? If you can get them hosted for free, you're supporting this site more than uploading them to the server . I'm on Opera, Mozilla might be different, and god help those on IE.

I don't have the A version, I have the K version - the only difference being that the K has one less aperture blade, 8 instead of 9. Or, in visual terms, 8 instead of 18, as odd-numbered blades turn out the highlights to look like they through an aperture of twice the blades.

It's weird that Pentax didn't do more odd-number-bladed lenses.

It is a nice lens. Of course, my example is in really bad nick, kinda loose and fungusy, but it does the job, and beatifully too, I might add. Actually, I can't really claim it does the job beautfully in my experience, as I didn't get many good pics from it.

This shows that the wider the ap, the steeper the learning curve, especially on a K-whatever-D standard focussing screen.

Split screens are better, as not only to they show when the subject's in focus, but they also show you how far you are from nailing the focus.

On an AF-only camera, often what happens, you'll hit focus but won't be able to stop turning the ring in time. The you start hunting back and forth - just like Pentax AF !

K100D, if you wish to see the reactions of another Torontoan to my lens, simply check here...
05-11-2008, 04:21 PM   #15
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QuoteOriginally posted by k100d Quote
really? didn't even know! all i know is it's big in Washington DC. i gotta start finding photo spots in Toronto once i have the time to shoot!
They usually bloom in the first week of May, I went there twice this year ( well it is my first year)

Here is some of the pictures I took in there.


lithos: What are you talking about you can't claim yours does beautiful job? The photo you showed me in that K50/1.2 thread was great!

Last edited by vizjerei; 05-11-2008 at 04:47 PM.
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