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03-23-2012, 06:02 PM   #1
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question about sharpness and zooming to check it

not sure if that is a great title but have a quick question

I have a pentax k-5 that i mostly use with a da ltd 35mm macro. Most shots i take i zoom either zoom in to max or nearly max on the camera or zoom in on lightroom or the like on my PC in order to view the amount of detail/sharpness/resolution of my exposure. Normally i am disappointed by these high magnifications and think that i must have done something wrong. But perhaps I am going about things the wrong way? Unless i am going to zoom and crop should i just judge the exposure without zooming?

what do you think?

many thanks

03-23-2012, 06:16 PM   #2
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Can you post a few shots along with 100% crops to give us an idea whether your expectations are too high or not?
03-23-2012, 06:38 PM   #3
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Regarding zooming on the camera: if you zoom to about 8x, that's full resolution. Above that, you'll start getting pixelation as you'd be zooming past 100%.

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03-23-2012, 06:43 PM   #4
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QuoteOriginally posted by dicko3000 Quote
Normally i am disappointed by these high magnifications and think that i must have done something wrong.
You Did Do Something Wrong! You Zoomed In!

No, seriously, most of us have a crap ton of lenses or a couple lenses that cover all ranges we need - at the same time, a lot of us are pretty technical shooters, a technical shooter is, amongst other things, one who doesn't cheat with massive crops of snaps. In short, if you are not cropping over a quarter of your snap away, then judge the exposure without zooming...

03-24-2012, 10:24 AM   #5
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A wild guess is that you're pixel peeping How far do you zoom in? 100%, 200%, ...

If everything is OK, 100% should be sharp. Higher zoom ratios will result in the PC (or camera) adding non existing pixels between 2 existing pixels using a wild guess (actually not that wild; it will probably take the difference of the two and spread it evenly it over the inserted pixels). So instead of a sharp edge, you will now have a slight slope in brightness.

It might also be expectation; if you take a landscape photo, don't expect to be able to recognize the individual leaves on a tree a mile away (with your 35mm lens); I tend to expect this and must always remind myself that that is not what can be expected.
03-24-2012, 10:55 AM   #6
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Even at 100% there will be some degree of softness which is greatly improved by sharpening but there shouldn't be obvious bluriness even at full magnification. I hazard a guess that particularly with macro photography there invariably isn't enough depth of field to render enough of the subject sharply, hence the need for focus stacking.
03-24-2012, 05:33 PM - 1 Like   #7
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Do a little test.

Set the camera on a good tripod, use the 2-sec self timer mode to turn off SR and lock the mirror, make sure the subject (preferably something with plenty of details) is stationary, use Live View for focus in Contrast AF mode, and use good lighting (e.g. a diffused flash) for correct exposure at a low ISO.

This way there will be no camera/lens/subject movement and the focus will be spot on.

Take the picture and review it on the computer at 100% after you applied moderate sharpness. It should look as good as the lens/camera combination can produce.

Then compare it with the pictures you normally take. If they as significantly softer, then most likely the focus is slightly off and/or there is motion blur.
03-25-2012, 06:29 AM - 1 Like   #8
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QuoteOriginally posted by dicko3000 Quote
not sure if that is a great title but have a quick question

I have a pentax k-5 that i mostly use with a da ltd 35mm macro. Most shots i take i zoom either zoom in to max or nearly max on the camera or zoom in on lightroom or the like on my PC in order to view the amount of detail/sharpness/resolution of my exposure. Normally i am disappointed by these high magnifications and think that i must have done something wrong. But perhaps I am going about things the wrong way? Unless i am going to zoom and crop should i just judge the exposure without zooming?

what do you think?

many thanks
QuoteOriginally posted by demp10 Quote
Do a little test.

Set the camera on a good tripod, use the 2-sec self timer mode to turn off SR and lock the mirror, make sure the subject (preferably something with plenty of details) is stationary, use Live View for focus in Contrast AF mode, and use good lighting (e.g. a diffused flash) for correct exposure at a low ISO.

This way there will be no camera/lens/subject movement and the focus will be spot on.

Take the picture and review it on the computer at 100% after you applied moderate sharpness. It should look as good as the lens/camera combination can produce.

Then compare it with the pictures you normally take. If they as significantly softer, then most likely the focus is slightly off and/or there is motion blur.
+1

You've left out a couple of important details about your "out of focus" issues. If you're taking photos at "higher" ISO's and you zoom in, yes, it will look "blurry" but this is the result of the ISO and not so much the lens/camera combo. Also, correct exposure AND accurate focusing go hand in hand in producing seemingly "sharp' photos. If you're taking photos of landscapes, even the smallest amount of camera and/or subject movement will not capture the image "razor" sharp. Understanding how to Post Processing works will help, just about every single photo you take will need some amount of sharpening and it's usually a subjective amount. Good place to start: Tutorials Sharpness

Personally, I have found that shutter speed will help immensely with "sharper" images. Unless, someone wants to share one, I have never seen a Full Resolution image posted on the internet that was not slightly "out of focus" (again subjective). Even "blurry" images when correctly PP and resized for internet purposes, look sharp.

And yes, I do zoom in to 100% to check for sharpness as well as heavily crop, it's all part of the game...

Guide to Image Sharpening


Last edited by theunartist; 03-25-2012 at 05:28 PM.
03-25-2012, 04:57 PM   #9
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100 percent magnification and lowest ISO and be sure the f stop is around 2 stops stopped down from wide open, or f 8 if you are not sure
03-27-2012, 02:53 PM   #10
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Thanks for all the responses and apologies for the tardy reply. I'll make sure I check at 100% and no farther and I'll set up that test shot.

Will report back.
03-27-2012, 06:05 PM   #11
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QuoteOriginally posted by joe.penn Quote
You Did Do Something Wrong! You Zoomed In!

No, seriously, most of us have a crap ton of lenses or a couple lenses that cover all ranges we need - at the same time, a lot of us are pretty technical shooters, a technical shooter is, amongst other things, one who doesn't cheat with massive crops of snaps. In short, if you are not cropping over a quarter of your snap away, then judge the exposure without zooming...

Hey! wait. I think ...i dont do this.

Oh noesss..

If ...err...if whats the opposite of a technical shooter? Can it be a practical shooter? please? Or critical? Critical shooter sounds cool too.

diabolical...maniacal...
03-28-2012, 03:03 PM   #12
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Adam: Thanks for that bit of info. regarding 8x magnification.

One thing I have definately noticed is that the make(?) of LCD screen definately affects the quality of the zoomed images. My Pentax K20D and Olympus E-520 DSLR's both have the same resolution of LCD, but the Pentax's image quality at 8x is still better than the Olympus' is at 3x. I can't take the Olympus screen past 3x (or on occasion past 5x) to be able to view sharpness, as anything past that is useless for that purpose. A curious thing though is that the liveview on the Olympus is definately much better than the Pentax's. Odd.
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