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08-27-2010, 06:26 AM   #1
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Just got my SMC M 50mm F1.4 lens yesterday

I got a nice example off ebay for $71 shipped and im quite happy with it. Its fast and its quite sharp but i find it really hard to focus peeping through the view finder. My eyesight isnt that great and what looks focus when i take the picture is not so good when viewing on the computer.

I have been using live view with 6x-10x zoom to find focus, but this takes a lot of time to setup a shot -- and some shots just dont wait for you. Find myself wishing i had a very nice autofocus / zoom lens.

I am quite pleased with the brightness and sharpness of images that are focused correctly. This is compared against an SMC A F2 and the kit lens 18-55mm da. SMC A F2 was complete garbage in my opinion and not even worth $20. Perhaps I had a bad example but at F2 the image quality was horrible. at F5.6 or so it was decent, but then the kit lens still seemed sharper.

If anyone wants to take a peep at the photos i snapped last night here is the link to my picasa album.

Picasa Web Albums - David Tiffany

I put a caption on all the photos taken with the 50mm M F1.4 lens, otherwise expect them to be the DA 18-55mm kit lens.

08-27-2010, 08:44 AM   #2
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The biggest problem with MF on this lens (or any other lens faster than f/2.8 or so) is that the DOF shows too much DOF. So there will *always* be things that appear in focus in the viewfinder that won't be in the picture. Best way to deal with this is to experiment and practice to learn to recognize this effect and strive to place your subject at the proper place within the focus zone to make sure it's really in focus. I like to practice using text on an angle. paying attention to which lines appear in focus in the viewfinder versus which actually turn out to be.
08-27-2010, 10:44 AM   #3
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For slow cheap autofocus with your M-lens, try Catch-In-Focus. Enable CIF in your main menu (sorry, I don't know which entry that is on the Kx) and set AF to AF.S. Now aim at a subject and slowly bring it into (center-weighted) focus while holding down the shutter. When you get focus confirmation, the shutter triggers.

You can also pre-focus on a spot where you expect a subject to appear. Aim and hold down the shutter; when the subject comes into focus, the shutter triggers. This is a handy technique when there's action around you.

One thing: CIF doesn't work when a lens is stopped-down very far, usually beyond f/8. This cutoff varies among different lenses. And CIF will trigger the shutter when focus confirmation first appears, not necessarily when what you want of a subject is actually in focus. It ain't perfect, but it's worth trying. My eyeballs are delaminating, so I use CIF a lot.
08-27-2010, 10:57 AM   #4
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Thanks for the tips rico, i already had been using the tactic to prefocus on a certain spot until the subject moves into that spot.

Currently my camera beeps when its in focus but your suggestion sounds a lot better.

I dont know if anyone was taken a peek at my photos but im pretty certain that the SMC m 50mm f1.4 is sharper with better colors then the kit lens.

08-27-2010, 03:02 PM   #5
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QuoteOriginally posted by buttons Quote
Thanks for the tips rico, i already had been using the tactic to prefocus on a certain spot until the subject moves into that spot.

Currently my camera beeps when its in focus but your suggestion sounds a lot better.

I dont know if anyone was taken a peek at my photos but im pretty certain that the SMC m 50mm f1.4 is sharper with better colors then the kit lens.
Some of them do seem to have a bit more richness to the color, although they are different subjects with different lighting.

Are you happy with your white K-x? I couldn't bring myself to do another color, just went with black.
08-27-2010, 04:02 PM   #6
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I have the M 1.7 and it's an amazing lens. However, my copy back-focused quite a bit. You might check to see if focus is spot on. With the K20D it was straightforward to adjust the camera to the lens. I've also used it with a split screen and that makes focus simple.
08-28-2010, 10:54 AM   #7
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There is no way a MF lens can backfocus. But it's certainly possible that something in the camera is physically not adjusted correctly. If the focus screen is positioned incorrectly, then focus would be off visually, but focus confirmation would be fine. If the AF sensors are positioned incorrectly, then focus would be fine visually, but confirmation would be off. Either way, a hardware adjustment is really in order. But it's also quite likely the problem is just the one I always point out in these situations (and in fact did a few replies above) - the viewfinder showing too much DOF, fooling you into thinking things will be in focus that won't be. There's no adjustment (short of replacing the stock focus screen with one optimized for faster lenses) that will change that.
08-28-2010, 02:26 PM   #8
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QuoteOriginally posted by Marc Sabatella Quote
There is no way a MF lens can backfocus. But it's certainly possible that something in the camera is physically not adjusted correctly. If the focus screen is positioned incorrectly, then focus would be off visually, but focus confirmation would be fine. If the AF sensors are positioned incorrectly, then focus would be fine visually, but confirmation would be off. Either way, a hardware adjustment is really in order. But it's also quite likely the problem is just the one I always point out in these situations (and in fact did a few replies above) - the viewfinder showing too much DOF, fooling you into thinking things will be in focus that won't be. There's no adjustment (short of replacing the stock focus screen with one optimized for faster lenses) that will change that.
Do you mean not enough DOF? With the exception of the M42 lenses (set on M), all lenses are wide open until shutter release time. If you want to get a true idea of What is in focus, the DOF preview is a useful tool to have and use. Because of that, somehow, your statement that the viewfinder is showing Too much DOF, has never made sense to me.

With the lens wide open, as it is pre shutter release, it might be difficult to tag sharp focus on a more distant subject. Even with AF confirmation sounding off, you've said yourself, that area is quite large, or can be compared to the subject. Closer distance, it won't have as much affect as you should be able to better see what you are focusing on. Larger DOF, if anything will render a sharper photo even if slightly BF or FF.

Or am I just nitpicking on terms?



08-28-2010, 02:31 PM   #9
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QuoteOriginally posted by Marc Sabatella Quote
There is no way a MF lens can backfocus. But it's certainly possible that something in the camera is physically not adjusted correctly. If the focus screen is positioned incorrectly, then focus would be off visually, but focus confirmation would be fine. If the AF sensors are positioned incorrectly, then focus would be fine visually, but confirmation would be off. Either way, a hardware adjustment is really in order. But it's also quite likely the problem is just the one I always point out in these situations (and in fact did a few replies above) - the viewfinder showing too much DOF, fooling you into thinking things will be in focus that won't be. There's no adjustment (short of replacing the stock focus screen with one optimized for faster lenses) that will change that.
QuoteOriginally posted by JeffJS Quote
Do you mean not enough DOF? With the exception of the M42 lenses (set on M), all lenses are wide open until shutter release time. If you want to get a true idea of What is in focus, the DOF preview is a useful tool to have and use. Because of that, somehow, your statement that the viewfinder is showing Too much DOF, has never made sense to me.

With the lens wide open, as it is pre shutter release, it might be difficult to tag sharp focus on a more distant subject. Even with AF confirmation sounding off, you've said yourself, that area is quite large, or can be compared to the subject. Closer distance, it won't have as much affect as you should be able to better see what you are focusing on. Larger DOF, if anything will render a sharper photo even if slightly BF or FF.

Or am I just nitpicking on terms?

I think what Marc is referring to is the fact that the stock focusing screens used in modern DSLR bodies can't show the true DOF below aperture around f/2.8. As a result, if you use fast glass at f/1.4 or f/2, you're actually going to see more DOF in the viewfinder than you will end up having in your image. That's why it can be a bit tricky to nail the focus with a stock screen using fast glass wide open.
08-28-2010, 07:25 PM   #10
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I remember a post here detailing a MF technique where the poster found his lens would focus better going from FF to focus point rather than BF to focus point. IOW he would start the focus in front of the subject and slowly focus out until the indicator lit rather than starting behind the subject and focusing back. He came upon this conclusion after thorough tests of the lens/body combination.
It made better sense when he explained it.
08-29-2010, 06:49 AM   #11
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For now I am just going to stick with using the live view for focusing. When my K-X beeps and I take the photo with this 50mm f1.4 lens it seems to be missing the focus by a few inches.

Some shots have a large enough depth of field that its fine, but close up images are not.
08-29-2010, 07:43 AM   #12
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Yeah the focusing is a little bit wonky for this lens. Mine acts the same way but I still love it for regular shooting. Closeup however are a bit annoying. but you'll get use to it with time I think.
08-29-2010, 10:35 AM   #13
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QuoteOriginally posted by JeffJS Quote
Do you mean not enough DOF? With the exception of the M42 lenses (set on M), all lenses are wide open until shutter release time.
I am not talking about shooting anything other than wide open. Yes, of course, when focusing a lens wide open but shooting at smaller aperture,e the shot will have more DOF than the viewfinder. but I was talking about focusing and shooting both wide open. So DOF preview doesn't enter into it - it has has no effect anyhow shooting wide open.

It's just an unfortunate fact of how modern DSLR focusing screens are designed that if your lens is f/2.8 or faster, then the viewfinder will show more DOF than will actually be in the shot when shooting wide open. It's possible to not notice on an f/2.8 lens, but beyond f/2 and especially when you get to f/1.4 it becomes pretty painfully obvious. When shooting text on an angle wide open at f/1.4, the viewfinder might show 6 lines in focus, but the shot will turn out to have only 2 lines in focus. So depending on which two lines end up actully being in focus and which lines you *wanted* to be in focus, this could masquerade as either FF or BF - or more likely, randomly and maddeningly go back and forth between those until you figure this out. Again, this is all using the stock screen - third party split prism screen won't have this effect.

Another way to see the effect I am talking abut is to mount your f/1.4 lens, set the aperture to f/2.8, and then do a DOF preview. If the DOF were being shown accurately, you'd see a huge increase in DOF while doing the preview (and you'd see the viewfinder darken two stops worth as well). But in fact, you'll barely see a difference at all until somewhere between f/2.8 and f/4 (at which points, it starts responding as it should). The stock focus screen is basically incapable of rendering images "correctly" at apertures beyond f/2.8 - in terms of both DOF and brightness, the viewfinder image will look more or less like f/2.8, even if the lens is actually f/1.4.
08-29-2010, 10:51 AM   #14
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Ok now I understand what you've been getting at.

08-29-2010, 12:06 PM   #15
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I barely understood that.
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