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09-20-2010, 12:56 AM   #1
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In focus through viewfinder but not on LCD preview?

Hey guys, I have a pentax-m 1.7/50mm that I bought on ebay. The problem is that it appears most of the time, when I am definitely in focus through the viewfinder, NOT the lcd/liveview, it is blurred/out of focus on the LCD preview and on my computer. What is the most likely culprit? Thanks in advance mates

09-20-2010, 01:02 AM   #2
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As with most that would ask here..post the photo with intact exif so that members can have a better data to go on in analyzing your problem.
For one thing the viewfinder might be loose.
Focus through live view and if that turn out focused when you upload the photo on your computer then compare the live view focus with the viewfinder and tweak the diopter to match the live view.
09-20-2010, 01:20 AM   #3
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Without seeing the photos we cannot be certain although this appears to be an issue with the thin DoF (Depth of Field) when using the lens wide open... its very difficult to distunguish exactly the focus as the image you see through the VF, also the does not correctly represent the DoF you will get in the final photo...

To nail focus I typically use liveview... use the digital zoom in liveview to see things clearer and adjust focus accordingly.... anothe rpossibility, although one where I dont have experience is to use a focus screen more adept at manual focussing at these apertures.
09-20-2010, 02:03 AM   #4
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If you are certain that an in-focus viewfinder image results in out-of-focus pictures, then your focus screen is not properly located.
Under you focus screen (between it and the pentaprism) is a metallic shim of a given thickness. This shim should have been chosen at the factory to exactly match your camera's specific internals, but in reality they just stick the same shim to all the cams... A lot of K7s are suffering from front focusing (the focus screen back-focuses, so the actual image will be front-focused), and I heard about some Kx having this problem too.

The solution is to replace this shim by another one with the appropriate thickness (thinner for front-focused pictures, thicker for back-focused pictures).
You can order a different shim from pentax, but you have to know which one you need, or buy several and pray that one will fit.

09-20-2010, 06:11 AM   #5
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I think you need to check whether being in-focus in live-view and in the final picture means being out of focus in the viewfinder.

If that's true then there's a problem (and it's in the camera, not the lens). If it's not true then maybe you are just finding it hard to judge focus well from the viewfinder. Which, frankly, is normal (at least for some cameras).

You don't mention what camera you have, or whether its auto-focus claims to be in focus. (In a K-x, in manual mode with a manual lens, the camera won't focus for you, but it will beep when you manually set the focus it would have set. I expect other Pentax cameras are similar. It can help.) Also, you don't mention using a tripod and I wouldn't trust any tests done without one.
09-20-2010, 08:42 AM   #6
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The viewfinder will always show *more* in focus a f/1.7 than really is (that's true for all apertures beyond f/2.8 or so). So unfortunately, it's normal for some things to appear in focus in the viewfinder but OOF in the picture or in liveview. However, the things in focus in the picture or liveview should *also* be in focus in the viewfinder. Mostly, it takes practice and experience to get to the point where you have some confidence that you have focused in such a way that your subject will be in focus in the picture - careful attention to whether the subject appears to be towards the front, back, or middle of the zone of acceptable focus. Or you can get a split prism focus screen.
09-20-2010, 09:08 AM   #7
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First thing I would check is a different lens. If things work correctly with another lens then the problem is the lens not the camera, so you can eliminate a lot of issues.

Assuming it is the lens, the second question I have is how much experience do you have with manual focus lenses? And which camera are you using? The k-x for example is difficult to use with manual focus lenses because the view finder was not designed for it. The in focus system will beep and the green hexagon will light up when in focus which helps but manual focus takes a lot of practice. Things can look fine in the view finder and not be in focus at all when you put them on the screen. This is especially true with the lens wide open since the DOF is very shallow.

In order to properly answer your question more information is needed as others have already said.

09-20-2010, 10:38 AM   #8
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Thanks guys I have a K-X, and I'm brand new to the DSLR/SLR scene, so a newbie to manual focus. I just took some pictures. One with it in focus during Liveview, and in focus in the final product. I switched to the viewfinder, and it was out of focus, so I rotated the focus ring to get it in focus, took the picture, and it was fine. Is there usually a discrepancy between the liveview and viewfinder? I thought they would be the same. Thanks in advance mates
09-20-2010, 11:21 AM   #9
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QuoteOriginally posted by SirJangly Quote
Thanks guys I have a K-X, and I'm brand new to the DSLR/SLR scene, so a newbie to manual focus. I just took some pictures. One with it in focus during Liveview, and in focus in the final product. I switched to the viewfinder, and it was out of focus, so I rotated the focus ring to get it in focus, took the picture, and it was fine. Is there usually a discrepancy between the liveview and viewfinder? I thought they would be the same. Thanks in advance mates
If you're new, that's probably the issue. I'm saying this as someone who was in your position four months ago, and still take shots at f2 or f1.7 and think I have a great shot until I go into Lightroom and see that I didn't get what I wanted in focus. It takes a lot of practice at those apertures, and until you perfect it, taking photos of moving objects is pointless.

Just keep getting some lens time with it and practice. You'll get there.
09-20-2010, 05:57 PM   #10
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QuoteOriginally posted by SirJangly Quote
Is there usually a discrepancy between the liveview and viewfinder?
See my previous post above. I answered that question quite specifically - yes, there is a difference when shooting f/2.8 or larger.
09-20-2010, 07:32 PM   #11
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If you are going to use the k-x with manual focus lenses do yourself a favor and get a split focusing screen. The focusing screen in the k-x (and most modern dslrs) is designed for auto-focus lenses.

I nearly gave up and went back to a point & shoot camera trying to get results with the stock screen. That doesn't mean you cannot get good results, just that you need to be a much better photographer than I am.

Try an eBay search for k-x focusing screen or check out the katzeye website or focusingscreen.com. I think if you search on this forum for either focusing screen or katzeye you will find lots of information.

And no there should not be a difference between live view and the view finder BUT there often is a perceived difference. When you are in focus do you get the green hexagon and "focused" beep?
09-20-2010, 09:43 PM   #12
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QuoteOriginally posted by jatrax Quote
First thing I would check is a different lens. If things work correctly with another lens then the problem is the lens not the camera, so you can eliminate a lot of issues.

Assuming it is the lens, the second question I have is how much experience do you have with manual focus lenses? And which camera are you using? The k-x for example is difficult to use with manual focus lenses because the view finder was not designed for it. The in focus system will beep and the green hexagon will light up when in focus which helps but manual focus takes a lot of practice. Things can look fine in the view finder and not be in focus at all when you put them on the screen. This is especially true with the lens wide open since the DOF is very shallow.

In order to properly answer your question more information is needed as others have already said.
What mode do I have to be in for the beep and green hexagon to work? Haven't seen it
09-20-2010, 09:44 PM   #13
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Nevermind set to auto and it worked I think I just need practice.
09-21-2010, 09:12 AM   #14
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Yep, practice, evaluate. Rinse and repeat. Remember that at wide apertures the depth of field will be very narrow.

The in focusing signals (beep and green hexagon) should be available in all modes as far as I know. Certainly available in Av, Tv, & M which are the ones I use most.
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