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02-07-2011, 09:19 AM   #1
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F/1.4 and F/2.8 with the FA 50mm f/1.4

The difference in depth of field as well as sharpness is quite significant.

f/1.4


f/2.8


is there any application for the f/1.4 aperture because i find it somewhat decent only at F/2.2 and above?

Even for flowers, i find it useful from F/4 onwards.


02-07-2011, 10:23 AM   #2
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1.4 is useful if you want less DOF or faster shutter speeds.
02-07-2011, 10:33 AM   #3
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Speed or rendering?

I believe the only way to decide on the fastest-fifties is to use one yourself and decide if you like the results.

I've always considered the f1.4 aperture to be a separate, special use lens with unique characteristics regardless of which actual lens it was associated with. The f1.4 & 1.2 lenses invariably had good optical and build qualities in keeping with their cost, but optical compromises were a reality of the design. Slightly slower lenses may have more useful mid-range attributes at lower cost.

Today perhaps the better questions are:

~ Do I want the f1.4 rendering and DOF attributes of that specific lens? (And am I willing to learn to use the lens to good effect?)

~ Do other qualities of the lens at smaller apertures make it equally, or more, desirable than, say, an f1.7 or f1.8 lens?

~ Can the higher ISO choices we have today be a substitute for the speed of the f1.4 - 1.2 lenses? I don't feel that pure lens speed is as critical today as it was in the film era. On the other hand, digital processing makes it possible to experiment with exotic options in ways not economically feasible before.

I recently sold an 8-element, Super Tak 50/1.4 because I wasn't using the f1.4 aperture characteristics and felt it should be put back in circulation as a classic lens to be experienced by the newer generation of Pentax users.

H2

Last edited by pacerr; 02-07-2011 at 11:20 AM.
02-07-2011, 04:38 PM   #4
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just to ask for owners of this lens...what do you do with f/1.4 generally?

02-07-2011, 04:42 PM   #5
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-Take pictures inside (no flash) where there is little light with my old camera that only goes to 1600 iso.
-Go for lots of OOF blur.

To some people these are very important, especially the second. Personally, I do most often use my FA50 at f/2.8 though.
02-07-2011, 04:52 PM   #6
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QuoteOriginally posted by Reportage Quote
just to ask for owners of this lens...what do you do with f/1.4 generally?
I use a Sigma 30mm f/1.4 (which is much better at f/1.4 than the image above but never has great corners at any f-stop). I have taken photos at f/1.4 in which virtually no slower lens could give me a shutter speed required. Here are two examples of shots which I think were at f/1.4

Camus Wyatt: Photographs | Latest
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02-07-2011, 05:54 PM   #7
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QuoteOriginally posted by pacerr Quote
I believe the only way to decide on the fastest-fifties is to use one yourself and decide if you like the results.

I've always considered the f1.4 aperture to be a separate, special use lens with unique characteristics regardless of which actual lens it was associated with. The f1.4 & 1.2 lenses invariably had good optical and build qualities in keeping with their cost, but optical compromises were a reality of the design. Slightly slower lenses may have more useful mid-range attributes at lower cost.

Today perhaps the better questions are:

~ Do I want the f1.4 rendering and DOF attributes of that specific lens? (And am I willing to learn to use the lens to good effect?)

~ Do other qualities of the lens at smaller apertures make it equally, or more, desirable than, say, an f1.7 or f1.8 lens?

~ Can the higher ISO choices we have today be a substitute for the speed of the f1.4 - 1.2 lenses? I don't feel that pure lens speed is as critical today as it was in the film era. On the other hand, digital processing makes it possible to experiment with exotic options in ways not economically feasible before.

I recently sold an 8-element, Super Tak 50/1.4 because I wasn't using the f1.4 aperture characteristics and felt it should be put back in circulation as a classic lens to be experienced by the newer generation of Pentax users.

H2
It's a pleasure to see such sensible thinking. No matter what the lens, I would use 1.4 only as a matter of total desperation. I'd rather push ISO and go to 2.0 or 2.8 than shoot at 1.4. I reached that conclusion quite early in the 30 years I've used 1.4 lenses.

The only thing I'd add is that 1.4 can sometimes be useful for focusing under very difficult conditions.

John

Last edited by John Poirier; 02-07-2011 at 05:59 PM. Reason: spelling
02-07-2011, 06:55 PM   #8
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QuoteOriginally posted by John Poirier Quote
The only thing I'd add is that 1.4 can sometimes be useful for focusing under very difficult conditions. John
While I can see a gain in brightness and a decrease in DOF (which may be used as a focusing aid) through about f2.0, I don't detect any improvement between f1.8 and f1.4 and have attributed that to the "effective aperture" limited by the VF itself. That opinion seems to be substantiated in the discussions regarding auto focus efficiency with apertures wider than about f2.8.

I just tried that again using an SMC-M 50/1.4 on a K200D. While using the DOF button in Manual mode change was observable from f5.6 through f2.0. Wider than that I could discern no apparent change through the view finder even though the change in DOF is present in the image itself.

But, maybe it's just the placebo effect, but I agree that the VF always SEEMS brighter using an f1.4 lens anyway, whether it's true or not.

Someone else may be able to clarify that concept.

H2

02-07-2011, 07:32 PM   #9
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QuoteOriginally posted by pacerr Quote
While using the DOF button in Manual mode change was observable from f5.6 through f2.0. Wider than that I could discern no apparent change through the view finder even though the change in DOF is present in the image itself.
Agreed, larger than f/2 on the K-7 = no change.
02-07-2011, 07:44 PM   #10
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This is why I kept the F50 f1,7 and sold my f1,4... Even at f1,8 the latter was not as sharp as the f1,7 wide open.

Still, there are things only a f1,4 will do, you just have to accept the compromises.
02-07-2011, 07:47 PM   #11
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I think the use of wide apertures really depends on the lens. I really never found the FA 50 to be usable wide open -- not so much due to depth of field, but more due to a general softness. Bokeh also gets a little strange wide open.

Depth of field is a factor not only of aperture, but also of distance to subject. so, if you were shooting a basketball game, you might find that you have decent depth of field shooting at f1.4.

There are lenses that are more usable wide open. The FA limiteds come to mind, the FA *85, and the DA *55 all seem to be sharper wide open (although even they will improve if stopped down a little bit).
02-07-2011, 08:03 PM   #12
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QuoteOriginally posted by pacerr Quote
While I can see a gain in brightness and a decrease in DOF (which may be used as a focusing aid) through about f2.0, I don't detect any improvement between f1.8 and f1.4 and have attributed that to the "effective aperture" limited by the VF itself. That opinion seems to be substantiated in the discussions regarding auto focus efficiency with apertures wider than about f2.8.

I just tried that again using an SMC-M 50/1.4 on a K200D. While using the DOF button in Manual mode change was observable from f5.6 through f2.0. Wider than that I could discern no apparent change through the view finder even though the change in DOF is present in the image itself.

But, maybe it's just the placebo effect, but I agree that the VF always SEEMS brighter using an f1.4 lens anyway, whether it's true or not.

Someone else may be able to clarify that concept.

H2
Hi.

You'll note that I said use of a 1.4 lens in difficult conditions is sometimes useful. It depends on ambient light levels and contrast, viewfinder brightness, the type of focusing screen, and the state of my eyes. among other things. I am certainly not suggesting it as a panacea. It was simply a suggestion based on many years of observations made with a wide variety of lenses and cameras. I view the viewfinder difference between 1.4 and 1.8 as a minor and somewhat unpredictable matter of convenience rather than a critical issue.

Looking through your viewfinder to detect minor brightness differences is not a bad idea, but we should all keep in mind that the human eye is not a scientific instrument. I wouldn't care to bet that its response to input in a given brightness range is linear or consistent over time, for example. There are also endless individual variations in how our eyes work, further complicated by how our brains might choose to perceive things at a given time.

If anyone cared enough to try, it would not be all that difficult to, for example, use a spot meter to measure relative viewfinder brightness while changing apertures.

Last edited by John Poirier; 02-07-2011 at 08:05 PM. Reason: spelling
02-07-2011, 11:16 PM   #13
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QuoteOriginally posted by John Poirier Quote
If anyone cared enough to try, it would not be all that difficult to, for example, use a spot meter to measure relative viewfinder brightness while changing apertures.
Just out of curiosity, I put the M 50/1.4 on an MX body (it has the best VF I own) for the first time in about 12 years (which is a shame) and re-discovered that subtle changes in perceived brightness and DOF are discernible all the way through f1.4 -- if the VF is good enough to take advantage of the fact.

While this capability isn't available with (most) "modern" bodies IMO it is possible. We just don't get to enjoy it any longer since one of the compromises of auto focus is penta-mirrors with crippled view finder economics. Considering the consumer demographics which grew up with AE/AF P&S cameras and never knew anything better this shouldn't be too surprising.

So I've gotta go with John's "sometimes" as being a true statement, but I can only wish it was still as true for my present day DSLR bodies. As it is, I've gotta go with the pragmatic combination of procedures and gear that work for me in actual practice.

[ How 'bout a 12 MPS sensor in a P3n-sized body with an MX view finder using micro-SD cards, selective ISO, AAA-sized batteries, selectable TTL center or spot metering and compatible with SMC-M and -A lenses? And no #@&^% in-camera flash bump to hide the aperture ring! I'd give up everything else (yes, including AF, AE and flash) from the modern SLR era for that very elegant package. ]

H2
02-07-2011, 11:50 PM   #14
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QuoteOriginally posted by pacerr Quote
Just out of curiosity, I put the M 50/1.4 on an MX body (it has the best VF I own) for the first time in about 12 years (which is a shame) and re-discovered that subtle changes in perceived brightness and DOF are discernible all the way through f1.4 -- if the VF is good enough to take advantage of the fact.

While this capability isn't available with (most) "modern" bodies IMO it is possible. We just don't get to enjoy it any longer since one of the compromises of auto focus is penta-mirrors with crippled view finder economics. Considering the consumer demographics which grew up with AE/AF P&S cameras and never knew anything better this shouldn't be too surprising.

So I've gotta go with John's "sometimes" as being a true statement, but I can only wish it was still as true for my present day DSLR bodies. As it is, I've gotta go with the pragmatic combination of procedures and gear that work for me in actual practice.

[ How 'bout a 12 MPS sensor in a P3n-sized body with an MX view finder using micro-SD cards, selective ISO, AAA-sized batteries, selectable TTL center or spot metering and compatible with SMC-M and -A lenses? And no #@&^% in-camera flash bump to hide the aperture ring! I'd give up everything else (yes, including AF, AE and flash) from the modern SLR era for that very elegant package. ]

H2
Thanks for doing that experiment. I still shoot quite a bit of black and white 35mm, mostly with LXs. Quite a difference from most digital SLR finders.

I'm with you on the digital body idea. I keep hoping that someone like Cosina will come up with a body with similar specs and interchangeable mirror boxes/lens mounts.

John
02-08-2011, 02:22 AM   #15
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A few thoughts about f/1.4 etc:

* As mentioned, a wide aperture provides thin DOF (but so do longer lenses) and usability in low light (without jacking-up the ISO, boosting noise).

* Superfasts are not macro/enlarger lenses with flatfield edge-to-edge sharpness. Use a lens @1.4 to grab otherwise impossible images, not to record fine detail.

* Some superfast shooters preferably (or always) leave the lens wide open, thinking, "Hey, I paid bookoo bucks for all this damn speed, I'm gonna USE it!"

* Does a 50/1.4 have too-thin DOF? It's not as thin as a 55/1.4, not even as thin as a 135/3.5 -- and I don't hear whining about slow 135s' DOF being too thin.

* Difficult focusing with thin DOF? Then use a KatzEye-type view screen; or learn to estimate distance, and prefocus; or stop-down the lens; or use Catch-In-Focus.

I like (but don't have much) fast glass -- no f/1.2's in my bag, just a few 50/1.4's -- FA, SuperTak and Yashica, with maybe an OM coming soon -- and a Tomioka 55/1.4. If I want thinner DOF, I can use an 85/2 or 135/2.8 or 200/4. Any such thin-DOF lens lets us surgically isolate a subject from their context. For the opposite, use a slow short lens, as found on every P&S digicam. My Tokina 21/3.8 @f/11 records every little speck. My Zenitar 16/2.8 @f/11 grabs even more photons.

But maybe I don't *want* to capture and show every little speck. Decide what's important: Every detail in the frame, or the subject. Choose a lens accordingly. I like using no-iris projector lenses, like a cheap 127/3.5, just because it leaves no doubt as to what I've focused on. There's a truism that painting is additive -- pile on more paint to achieve a desired image -- while photography is subtractive -- remove unneeded elements until only what's necessary remains. That's what thin DOF is for, to remove the extraneous.
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