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01-08-2010, 08:45 PM   #1
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New K-7 ISO & focusing questions

Hi - I just got my first ever SLR 2 days ago - the K-7. I chose it over the Nikon D90 for the build quality, WR, and of course all the great info on this and other forums.
I have just a couple of quick questions. The manual and some reviews seem to indicate that Auto ISO should be available in 'P' program mode (and for that matter, Tv,or Av modes).
On my camera ISO will only go into 'auto' in Green or Tav modes. Any other K-7 users find the same thing? If so, then that's possibly the way it's supposed to be. But I find myself in program mode adjusting shutter or aperature and the ISO is stuck wherever I left it last. Page 90 of the manual - grey box - says "when the exposure mode is set to Sv, M, B, or X - the sensitivity cannot be set to AUTO."
I should mention that I updated to the 2.0 firmware the first day I had the camera, and I don't know how it worked before then.
Also, I have a question about focus. I have the 18-55 and 50-200 WR lenses. I tried to focus on a pine tree about 75 yards away in bright sunlight over snow, and when I zoomed in on the photo, it seemed very out of focus. I used center (spot) focusing. I increased the sharpness, and that seemed to help somewhat. Does focus have anything to do with sharpness? I read some forums that other users increase exposure or sharpness on all images.
I downloaded a focus chart by Yvon Bourque, and preliminary trials indicate the smc DA18-55 lens is autofocusing properly, with very little difference between -10 and +10. I'm just wondering if there may be a focusing issue I should watch for, or if sharpness is a standard complaint.
I appreciate it anyone has a moment to respond briefly to either of these concerns. I look forward to learning how to use my new camera, and will continue to scour this forum for helpful tips.

Thanks, dclauria

01-09-2010, 12:18 AM   #2
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Try pressing the ISO button and the Green Button while in Program Mode... you will see "auto" will be displayed beside the ISO setting.


Cheers

Neil
01-09-2010, 09:50 AM   #3
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I don't have the K7, but you should be able to use auto iso in program as well as Av and Tv modes. As far as focus, how sharp your photo is depends on how much you stop down your lens. that is to say, if you take a photo with the kit lens wide open, you may see some softness in it, whereas if you take a photo around f8, it will be very sharp. I personally doubt that there is much actual focus error on the lens, but you could post a photo or two and see.
01-09-2010, 10:10 AM   #4
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Thanks! Green button solved problem with Auto ISO

Thanks for the help. Pressing the ISO and Green button at the same time took care of the problem - I now have Auto ISO. It seems like I would have seen that in the manual. Anyway, I'm going to do some more reading in the beginner's forum-especially the Green button usage! Thanks again.

01-09-2010, 01:41 PM   #5
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QuoteOriginally posted by dclauria Quote
It seems like I would have seen that in the manual.
Page 90 of the K-7 user manual:

"You can set the sensitivity to suit the brightness of the surroundings. The sensitivity can be set to AUTO or within a sensitivity range equivalent to ISO 100 to 3200. The Default setting is AUTO.

...

Press the Green button while pressing the ISO button to return to AUTO"


edit: I've found that the manual is in fact quite thorough. The only problem is I read it while the battery was charging, so I couldn't follow with the camera. I had to re-read it with the camera actually in hand to remember anything.
01-09-2010, 05:25 PM   #6
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Wow! I can't believe I missed that! (on page 90)

This afternoon I was reading the manual with camera in hand sitting in a ski lodge while my son was out breaking his wrist snowboarding. He's at the emergency room right now with his mother. Anyway - yes - I agree, you learn a lot more that way.

Thanks!
01-09-2010, 06:22 PM   #7
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QuoteOriginally posted by dclauria Quote
Hi -
Also, I have a question about focus. I have the 18-55 and 50-200 WR lenses. I tried to focus on a pine tree about 75 yards away in bright sunlight over snow, and when I zoomed in on the photo, it seemed very out of focus. I used center (spot) focusing.
The "kit" lenses are made to sell at a low price, so are not made to tolerance as strict as DA* lenses (or any other "pro" lenses). Hence, the focus changes a little bit as you zoom in and out. For that reason, it is better to zoom first, then focus.
01-09-2010, 09:28 PM   #8
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Most liekly, the camera simply focused on a different branch of the tree than the one you zoomed in on, and you weren't shooting at a small enough aperture for the depth of field to encompass the entire tree.

01-10-2010, 07:54 PM   #9
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QuoteOriginally posted by Marc Sabatella Quote
Most liekly, the camera simply focused on a different branch of the tree than the one you zoomed in on, and you weren't shooting at a small enough aperture for the depth of field to encompass the entire tree.
at 75 yards? that's one fat tree!!!
01-10-2010, 08:22 PM   #10
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OK, or maybe something else in the foreground or background. Without sample images and info on *how* the OP tried to force the camera to focus on the tree, it's hard to say.
01-10-2010, 10:20 PM   #11
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Thanks for your patience in responding to this thread.

I had just typed a long reply about the how I took the photos handheld with widest aperture - thus the resulting operator error, and I lost my whole post.

Suffice it to say I realize that when I magnify the image completely, it will not be sharp or in focus. Is this correct?

Also, I did some more tests in doors with flash, medium aperture, on a tripod - 8 to 10 feet from a vertical focus chart and have adjusted the 18-55mm lens to -5 focus adjustment, and left the 50-200m lens at 0.

Wide angle lenses will not achieve as good a focus as a telephoto lens at the same distance from the subject (such a very small bar code on a bookshelf) because they can't discriminate the focus point as well - correct? My telephoto lens faired much better.
01-11-2010, 11:10 AM   #12
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*Something* should be in focus even viewed at 100%, but it certainly won't look as sharp as it does otherwise. Images from inherently sharper lenses will look *better* at 100%, but pretty much nothing out there will be maximally sharp at 100%, especially when shot wide open.

And no way should any lens require any sort of adjustment based on a test shooting at medium aperture. The kind of focus errors these adjustments are designed to fix are measured in millemeters. The DOF of your lens should be completely masking that. Any discrepancy at medium apertures you see would be the result of testing error. Chances are, you'd never get shallow enough DOF with the kit zooms to ever see a focus error of this sort.
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