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01-10-2019, 01:06 PM   #706
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QuoteOriginally posted by house Quote
f2.8 or f1.4 makes a difference in terms of iso/shutter speed. Changing sharpness across the field is more problematic than slightly lower sharpness for flat subjects as it's more noticeable. Buying the da* 55mm for portraits and the dfa 50mm macro for flat shots cost the same as buying one DFA* 50mm f1.4.
I paid $500 for my DA*55 and $250 for a used FA 50 macro. And after buying DFA 50 1.4 I'd still need macro. Not even close.
Look in your library, see how often you need a sharp edge to edge 1.4. If you're like me from the 2000 keepers last year, I don't have one.
How many do you have?

QuoteOriginally posted by house Quote
f2.8 or f1.4 makes a difference in terms of iso/shutter speed
I suppose it can, theoretically, but I don't have single example, maybe someone else does. If it were me the probability would be a 0% chance of being relevant. 0 out of 2000 is a pretty convincing number.

The house image above is ISO 100, ƒ1.4 at 1/800s. That's as close as I come. And I just took a shot on the move walking up the driveway. It would have been better at ƒ5.6 and 1/60s. It could have been better with a 5.6 lens, because I wouldn't have had to remember to change settings to get better.


Last edited by normhead; 01-10-2019 at 01:17 PM.
01-10-2019, 01:33 PM   #707
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I suspect the dfa 50 1.4 is simialr to the Sony FE 50 1.4 ZA which has a flatter field than the Zeiss 50 f2 Makro Planar at infinity.
"Remember, though, this is the field of focus at infinity. This is a Makro lens so it has a much flatter field at close distances. Non-macro lenses usually don’t change their field of focus all that much at closer range."
01-13-2019, 09:35 AM - 1 Like   #708
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QuoteOriginally posted by reh321 Quote
The new standard is corner-to-corner perfection.
Lenses like the Zeiss standard and the "Zeiss killer" eight-element 50mm f/1.4 Takumar concentrated on the center of the image.
QuoteOriginally posted by UlrichSchiegg Quote
Film can take light that comes at an angle, digital sensors cannot (also explaining the curved sensor discussion). Some of it is corrected with the edge-micro-lenses in front of the sensor.

In other words, your Takumars edge performance on film is much better than on digital.
QuoteOriginally posted by clackers Quote
Not really a problem for a DSLR, UlrichSchiegg.

The registration distance is nice and long so that the light is coming in quite parallel, it's mirrorless that have this problem because the sensor is now so close to the rear element.

Much worse in an ultra-wide, BTW.
I don't understand your comment, how it relates to what I have written.

Digital and film lens design and "recording" have principle design differences. Digital lenses are constructed more towards "telecentric" beam of light guidance and longer exit pupil compared to film lenses. Lenses designed towards telecentric optic get longer. Microlens-shifting in front of digital sensors is done to improve the edge performance, which wasn't needed for film because it could take light at an angle.

There is not much that can be read in the open literature about lens design, but this is some of the basics that you can find. Also that it is used for DSLR and not just the compacts.
01-13-2019, 09:51 AM - 1 Like   #709
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QuoteOriginally posted by UlrichSchiegg Quote
I don't understand your comment, how it relates to what I have written.

Digital and film lens design and "recording" have principle design differences. Digital lenses are constructed more towards "telecentric" beam of light guidance and longer exit pupil compared to film lenses. Lenses designed towards telecentric optic get longer. Microlens-shifting in front of digital sensors is done to improve the edge performance, which wasn't needed for film because it could take light at an angle.

There is not much that can be read in the open literature about lens design, but this is some of the basics that you can find. Also that it is used for DSLR and not just the compacts.
I tend to look at what the lens does, not what it's designed for.

My favourite story as a point of illustration.

Al Cooper was hired as studio musician for Bob Dylans Hwy 61. He was hired to play guitar but Micheal Bloomfield was there and he was absolutely outclassed. So he sat down at one of the studio organs and started fooling around. He laid down a track that eventually became the lead riff in one of the songs. One of the other musicians complained "he's not even an organist". To which Dylan replied "Don't tell me who is and who isn't an organist."

So basically, unless you have some pretty convincing evidence of the superior performance of digital lenses over lenses designed for film, I see no useful purpose for such differentiation.

In a previous post I mentioned that the FA 50 macro outperforms the DFA 50 1.4 for edge to edge performance, even though it's a "designed for film" lens. If the notion you posted above is true, then I would assume you have some kind of empirical evidence showing it to be the case. After all, no one cares if designs have been altered for digital based on some special design criteria, if it makes no difference to the recording characteristics of a digital camera system,

I also don't pay much attention to the manufacturers resolution numbers, that are based not on testing but on running the designed lens through a computer analysis. I really don't care what they are designed for. I only care about how the lens performs in the field.

A good lens is a good lens. Most of us are still waiting for the digital lenses that will replace the 31 ltd and 77 ltd. That those lenses were designed for film, really doesn't cut is as photographic criticism. Who cares if they were designed for film, if digital designs haven't surpassed them? And in the comparisons I've seen, nothing in the big heavy Sigma art series that are designed for digital surpasses or even equals them.


Last edited by normhead; 01-13-2019 at 10:02 AM.
01-13-2019, 11:54 AM   #710
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QuoteOriginally posted by normhead Quote
I tend to look at what the lens does, not what it's designed for.

My favourite story as a point of illustration.

Al Cooper was hired as studio musician for Bob Dylans Hwy 61. He was hired to play guitar but Micheal Bloomfield was there and he was absolutely outclassed. So he sat down at one of the studio organs and started fooling around. He laid down a track that eventually became the lead riff in one of the songs. One of the other musicians complained "he's not even an organist". To which Dylan replied "Don't tell me who is and who isn't an organist."

So basically, unless you have some pretty convincing evidence of the superior performance of digital lenses over lenses designed for film, I see no useful purpose for such differentiation.

In a previous post I mentioned that the FA 50 macro outperforms the DFA 50 1.4 for edge to edge performance, even though it's a "designed for film" lens. If the notion you posted above is true, then I would assume you have some kind of empirical evidence showing it to be the case. After all, no one cares if designs have been altered for digital based on some special design criteria, if it makes no difference to the recording characteristics of a digital camera system,

I also don't pay much attention to the manufacturers resolution numbers, that are based not on testing but on running the designed lens through a computer analysis. I really don't care what they are designed for. I only care about how the lens performs in the field.

A good lens is a good lens. Most of us are still waiting for the digital lenses that will replace the 31 ltd and 77 ltd. That those lenses were designed for film, really doesn't cut is as photographic criticism. Who cares if they were designed for film, if digital designs haven't surpassed them? And in the comparisons I've seen, nothing in the big heavy Sigma art series that are designed for digital surpasses or even equals them.
Oh, fully fine.

I just have another gene, its name is curiosity.
01-13-2019, 12:23 PM - 1 Like   #711
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QuoteOriginally posted by UlrichSchiegg Quote
Microlens-shifting in front of digital sensors is done to improve the edge performance, which wasn't needed for film because it could take light at an angle.

.
My Sony A7 has a so-called 'thick stack' of microlenses on the sensor, my Pentax K-1 does not, it's a DSLR with a longer registration distance because a mirror is accommodated.



01-13-2019, 01:28 PM   #712
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QuoteOriginally posted by clackers Quote
My Sony A7 has a so-called 'thick stack' of microlenses on the sensor, my Pentax K-1 does not, it's a DSLR with a longer registration distance because a mirror is accommodated.
Thank you for the info. I didn't know that this differentiates the Sony from the K-1. And I see the point. But maybe with larger back lens diameter it improves, so the Nikon Z may not need it either. Or maybe the Sony wanted better edge performance and improved it at the higher costs. Or maybe Pentax didn't care for those apertures appearing like the F0.95.

01-13-2019, 02:02 PM - 1 Like   #713
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QuoteOriginally posted by normhead Quote
I tend to look at what the lens does, not what it's designed for.

My favourite story as a point of illustration.

Al Cooper was hired as studio musician for Bob Dylans Hwy 61. He was hired to play guitar but Micheal Bloomfield was there and he was absolutely outclassed. So he sat down at one of the studio organs and started fooling around. He laid down a track that eventually became the lead riff in one of the songs. One of the other musicians complained "he's not even an organist". To which Dylan replied "Don't tell me who is and who isn't an organist."

So basically, unless you have some pretty convincing evidence of the superior performance of digital lenses over lenses designed for film, I see no useful purpose for such differentiation.

In a previous post I mentioned that the FA 50 macro outperforms the DFA 50 1.4 for edge to edge performance, even though it's a "designed for film" lens. If the notion you posted above is true, then I would assume you have some kind of empirical evidence showing it to be the case. After all, no one cares if designs have been altered for digital based on some special design criteria, if it makes no difference to the recording characteristics of a digital camera system,

I also don't pay much attention to the manufacturers resolution numbers, that are based not on testing but on running the designed lens through a computer analysis. I really don't care what they are designed for. I only care about how the lens performs in the field.

A good lens is a good lens. Most of us are still waiting for the digital lenses that will replace the 31 ltd and 77 ltd. That those lenses were designed for film, really doesn't cut is as photographic criticism. Who cares if they were designed for film, if digital designs haven't surpassed them? And in the comparisons I've seen, nothing in the big heavy Sigma art series that are designed for digital surpasses or even equals them.
Well, I think the big issue with film era lenses is that they are quite prone to purple fringing. And every one of the FA limiteds is a culprit.

As far as the 50 macro outperforming the DFA 50 f1.4, it is difficult for me to say when it can't shoot at f1.4 to f2.8. On the other hand, if you need flat field and macro ability, the DFA *50 isn't going meet those needs either.

Ephotozine tested both lenses: Pentax SMC P-D FA 50mm f/2.8 Macro Lens Review and HD Pentax-D FA 50mm f/1.4 SDM AW Lens Review Bearing in mind that the DFA 50 macro was tested on APS-C and the DFA *50 on a K-1, I do think the edge performance of the DFA *50 is considerably better than the macro.
01-13-2019, 02:52 PM   #714
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QuoteOriginally posted by UlrichSchiegg Quote
Thank you for the info. I didn't know that this differentiates the Sony from the K-1. And I see the point. But maybe with larger back lens diameter it improves, so the Nikon Z may not need it either. Or maybe the Sony wanted better edge performance and improved it at the higher costs. Or maybe Pentax didn't care for those apertures appearing like the F0.95.
Yeah, you can google 'retrofocal lenses' or similar to see the mirrorless problem.

A larger mount diameter *does* help, this is a Sony and Fuji problem because their mirrorless mounts were both designed for APS-C.

By starting from scratch, Nikon are showing off with that f0.95 lens because to try that on Sony's E mount would result in embarrassing wide open performance. Mitakon are brave enough to make one, but I don't know how bad it is.

Canon had the same problem with their mirrorless EF-M mount.

It's a disaster like that, no matter how many units they sold they'll probably have to orphan it and put their efforts into the RF Mount that's wide enough for high performance lenses.

Btw, K Mount is fine, it was originally for 35mm film, of course.
01-13-2019, 03:05 PM   #715
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QuoteOriginally posted by Rondec Quote
Ephotozine tested both lenses: Pentax SMC P-D FA 50mm f/2.8 Macro Lens Review and HD Pentax-D FA 50mm f/1.4 SDM AW Lens Review Bearing in mind that the DFA 50 macro was tested on APS-C and the DFA *50 on a K-1, I do think the edge performance of the DFA *50 is considerably better than the macro.




Using your source the DFA 40 drop out of the excellent edge race at 5.6, the macro not until ƒ11. Given they are both test on aK-1 on the other site, I'm not sure how this one tells you the DFA is better.
01-13-2019, 03:19 PM   #716
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QuoteOriginally posted by normhead Quote



Using your source the DFA 40 drop out of the excellent edge race at 5.6, the macro not until ƒ11. Given they are both test on aK-1 on the other site, I'm not sure how this one tells you the DFA is better.
If you read the review, it clearly says that the DFA 50 macro was tested on a K5 IIs. The assumption has to be that the edges will be worse on a K-1 than reported here.

But in a sense you are right, you shouldn't buy a DFA *50 to shoot it mainly at f11. It shines at wide apertures.

I'll say again. I have a DA *55 and it is fine for my purposes. I don't need excellent sharpness at f1.4. But I also think we need to be honest that there aren't many other lenses out there that give this sort of border sharpness at similar apertures.
01-13-2019, 03:47 PM   #717
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Actually I would call the D FA* 50mm's performance remarkably uniform - and this lens is almost diffraction limited.
The "excellent" range is not defined on the D FA* chart; ephotozine obviously switched to a numeric representation. The D FA* losing resolution mainly in the corners is a bit weird, unfortunately I don't know of any other test to double check (actually I'm amazed about the wide-open performance - although I've never seen any hint of unsharpness on my sample -, and I'd like to double check that, too).
Still, between f/4 and f/11 we're talking about some 10%. Similar to what the D FA macro is losing, but between f/8 and f/11. And when the D FA macro starts (that is, f/2.8), the D FA* is at peak performance already.

Considering we're talking about different types of lenses, I have a hard time accepting that the D FA* 50mm isn't better as a non-macro normal.

If shooting at f/11, most lenses would do.
01-13-2019, 03:55 PM   #718
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I read somewhere that theoretically lenses are sharpest wide open (perhaps its just diffraction) and that the best lenses tend to follow that pattern. Being best at larger apertures.
01-13-2019, 04:02 PM   #719
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QuoteOriginally posted by house Quote
I read somewhere that theoretically lenses are sharpest wide open (perhaps its just diffraction) and that the best lenses tend to follow that pattern. Being best at larger apertures.
No, I've never seen a lens or read a performance chart for one where best performance didn't occur one to two stops down.

The light from the edges is inferior to the light coming straight on. The more you open a lens the more of this poorer light you have to correct or deal with.
01-13-2019, 04:09 PM   #720
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QuoteOriginally posted by house Quote
I read somewhere that theoretically lenses are sharpest wide open (perhaps its just diffraction) and that the best lenses tend to follow that pattern. Being best at larger apertures.
That would be a diffraction limited lens. They're very rare.
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