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08-29-2015, 03:59 PM - 1 Like   #16
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QuoteOriginally posted by Adam Quote
You're probably not going to be able to tell the difference (especially on film) unless you plan to leverage the faster F stop for bokeh.
Just to be sure, this especially applies more to digital. More importantly you have to know what tests are being conducted, how they are conducted and how the results are to be evaluated. With film there is that additional step on how to extract the information from it.

I test all my lenses since I do buy a lot of used equipment as I wouldn't really know if they are up to original factory specs nor do I know wha those faactory specs are. I like to weed them out so that if I need to count on them, I will know what can be expected. Below are the results of testing my Pentax 50mm lenses using a 2X2 arrangement of the ISO12233 chart, properly lit, tripod mount with my 14.6MP Pentax K20D.

Lenses


Results

Full res version -> Pentax 50mm Lenses

Using the K20D, I can establish a baseline by comparing it to results from others like DPREVIEW showing the 14.6MP K20D ideally attains about 24 -> Pentax K20D Review: Digital Photography Review

Since I do use film, I also conducted this test but this time with a 4X4 arrangement of the ISO12233 chart, properly lit, tripod mount using my K20D with a known baseline but also this time on Kodak Techpan @ ISO25 processed in Technidol and then scanned 4000dpi on Coolscan. As shown below, this combination achieves much higher results of about 30~36 with the Pentax SMC Macro 50mm F4 on my Pentax LX[B].

Taking it further, I used the Pentax Autobellows to take a peek at the frame of film at about 4.5X magnification and as you can see from the far right blowup, this lens+film combination actually achieves an even higher 52. Like I said, the challenge with scanning is being able to resolve all the detail that is captured on the film.


Full res version -> Pentax SMC Macro 50mm f4 series

Since I don't really know how these lenses are supposed to perform brand new, I still don't know what is the limiting factor in these tests. However, I do know that the lenses are not the bottleneck at least when it comes to resolution.

BTW, I have now had considerable experience shooting the 50mm f1.2 on my film bodies as well as the K20D and I can tell you that a handheld shot with the K20D's tiny viewfinder - compared to the giant viewfinders in the film bodies, yields very poor results in achieving critical focus. Even in bright scenes, I am lucky to get a sharp wide open shot with the K20D in 5 or more attempts but have no problem nailing each with my MX or LX.

08-29-2015, 04:01 PM   #17
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QuoteOriginally posted by Lenscap Quote
Good points about hitting the focus with a 1.2 DOF. My eyes aren't what they used to be, and the combination of dim enough light to require f/1.2 and that crazy-shallow DOF might be an issue. (I have come to really appreciate the little flip-out magnifier on my TLR.)


Edit to add: at the moment, I don't own a DSLR. I'm using film SLRs, and digital P&S for everyday snapshots.
I only shoot film and find focusing my K50/1.2 @ 1.2 hard as well (Getting too old)

I find a tripod and K Series magnifier helps a lot on close focused subjects. At night shooting @1.2 is no problem, as most shots are at infinity and a tripod is a must.

Phil.
08-29-2015, 04:36 PM   #18
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QuoteOriginally posted by LesDMess Quote
Below are the results of testing my Pentax 50mm lenses using a 2X2 arrangement of the ISO12233 chart, properly lit,
Surprised to see how close the results are, and how much better the A f2.0 shows than the Mf2.0. Thought they had the same formula.
08-29-2015, 04:47 PM   #19
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QuoteOriginally posted by arnold Quote
Surprised to see how close the results are, and how much better the A f2.0 shows than the Mf2.0. Thought they had the same formula.
Since these are used - and I don't really know what factory new results are supposed to be, I don't have a reference point of knowing if these are what they are supposed to be or not.

08-29-2015, 05:34 PM   #20
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QuoteOriginally posted by LesDMess Quote
Since these are used - and I don't really know what factory new results are supposed to be, I don't have a reference point of knowing if these are what they are supposed to be or not.
I think the A lenses have a better coating (they definitely look more "red" than the Ms), my A 50mm f1.4 is better than the M f1.4. It also have a nice bid dots bokeh the M lens doesn't have.

08-29-2015, 06:41 PM - 1 Like   #21
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QuoteOriginally posted by Cuthbert Quote
I think the A lenses have a better coating (they definitely look more "red" than the Ms), my A 50mm f1.4 is better than the M f1.4. It also have a nice bid dots bokeh the M lens doesn't have.
Can't say that I have quantified coating and bokeh characteristics much. The OOF elements in your picture appear to be "swirly" and not "solid". Is that due to movement?
08-29-2015, 10:41 PM - 1 Like   #22
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Okay, so it's unanimous, then: the f/1.4 is the best. Except the 1.7 is better. And the f/1.2 isn't good enough to be worth the money, except it actually is. And the f/1.8 55 is better than all of them, except it's not. Right?

I'm being facetious, of course, but it sounds like each user has his or her own preference, and I guess the message is that I have to figure out my own preference.

What I can say at this point is that I have been pleased with my 1.7s. Any shots I've gotten that were less than what I expected have been attributable to me, not the lens.

I think I have to try a 1.4 just to see the reaults. As for the 1.2, if I find a bargain, I'll give it a shot. Haven't made my mind up on the 1.8 55 yet, but if I can find a good one, it'd be worth a shot.

I thank you all for your insight. You've given me a lot to think about.
08-30-2015, 12:02 AM   #23
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I have the following lenses in 50mm primes.

A F2
A F1.7
A F1.4
M F1.4

Of them all, the main one I use is the A F1.7. Great lens, fast enough for most stuff, sharp as, AND if something happens to it I can easily afford to just buy another one.

the M 1.4 stays on the MX body for pretty much ever, nice lens but I personally find it's not as sharp as the 1.7 (although, perhaps mine isn't the best example)

the A1.4 I only got today, so havent actually used yet.

08-30-2015, 03:52 AM   #24
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QuoteOriginally posted by Lenscap Quote
Okay, so it's unanimous, then: the f/1.4 is the best. Except the 1.7 is better. And the f/1.2 isn't good enough to be worth the money, except it actually is. And the f/1.8 55 is better than all of them, except it's not. Right?

I'm being facetious, of course, but it sounds like each user has his or her own preference, and I guess the message is that I have to figure out my own preference.

What I can say at this point is that I have been pleased with my 1.7s. Any shots I've gotten that were less than what I expected have been attributable to me, not the lens.

I think I have to try a 1.4 just to see the reaults. As for the 1.2, if I find a bargain, I'll give it a shot. Haven't made my mind up on the 1.8 55 yet, but if I can find a good one, it'd be worth a shot.

I thank you all for your insight. You've given me a lot to think about.
Given all the above evidence I think you have made the perfect summary.
08-30-2015, 04:41 AM   #25
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QuoteOriginally posted by LesDMess Quote
Can't say that I have quantified coating and bokeh characteristics much. The OOF elements in your picture appear to be "swirly" and not "solid". Is that due to movement?
No, it's the bokeh of the lens, that is "swirly" without actual swirl.

Yours doesn't have the same bokeh?





08-30-2015, 06:24 AM - 1 Like   #26
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Many years ago I read a post on PDML covering the same topic. In sum, it stated the 1.7's and 1.8's (including Takumar lenses) were designed for 'flat work' on a copy stand,



so they are intentionally sharper edge-to-edge than the 1.4's and 1.2's. The 1.4's were intentionally designed to be softer at the edges to meet the then-current taste in pleasing images (subject centered and brought forward by soft surrounding detail). The 1.2's were designed for an entirely different image and purpose; they seem to marry the two preferences in the near focus regions and offer a different out-of-focus-area rendering (and have the advantage of transmitting more light while focusing).

In the digital age, contemporary taste seems to have shifted to edge-to-edge sharpness, lending a stronger preference for the slower, flatter specifications and a change in design philosophy for new lenses.

It's important to understand that flat-work, for instance, photographing a typeset layout board (to make a 'burn' negative - or an image negative cut and taped into the 'burn' neg) to make an offset printing plate hasn't been performed with cameras for thirty or so years.

These lenses are neither 'good' nor 'bad' in and of themselves, nor are our preferences for what constitutes a pleasing image today, versus 50 years ago. The lenses haven't changed but our preferences have. Knowing your preference of final image characteristics will help selecting your 'class' of lens.

Last edited by monochrome; 08-30-2015 at 07:20 PM.
08-30-2015, 03:25 PM   #27
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Some say the XR Rikenon 50/2 is the sharpest Pentax K-mount "normal" lens.

Chris
08-30-2015, 06:42 PM   #28
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Yet another lens I'm not familiar with. How many non-pentax K mount 50's are out there? I'm thinking it must be, to use a scientific term, a buttload.
08-30-2015, 07:15 PM   #29
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Look in the third-party lenses review section, legacy primes, under Ricoh
08-31-2015, 11:41 PM   #30
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I think you should try for yourself, then decide. Its personal. I tried and I like 1.7 lens better then 1.4 (lens iterations are M and in F). I don't care about hair splitting sharpness, but I like look of 1.7 better: its more contrasty, it has more interesting and swirly bookeh wide open.
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