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03-19-2016, 11:10 AM   #1
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Tack Sharp??

Hi,

Iv recently aquired a Pentax K5 as my first DSLR, whilest i am happy with the camers Im not sure if im encountering issues with focusing and producing tack sharp images.

Im trying to focus on the subjects eyes and when im zooming in 1:1 in lightroom they dont appear razor sharp.

Im using the 50mm f1.8 smc da lens - via my example image, I dont know if this is what should be produced or if i have unrealistic expectations.

TIA

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03-19-2016, 11:35 AM   #2
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At that size it is hard to see the eyes. The left side of his face is pretty shadowed. I would expect f/5.6 would give you decent sharpness with that lens, but focus is important. How did you focus the sample shot?
03-19-2016, 11:38 AM   #3
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Manual focus or auto?

If manual check your diopter setting.

If auto do an autofocus test using a tripod and a focus test target to rule out front/back focus which needs adjustment.

Also what aperture are you using? At f/1.8 your depth of focus might be too small increase the aperture and try again.

At very small apertures even a slight movement as you press the shutter button can cause your focus to be off so check your stance and holding/breath control.
03-19-2016, 11:39 AM   #4
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QuoteOriginally posted by Nick Siebers Quote
At that size it is hard to see the eyes. The left side of his face is pretty shadowed. I would expect f/5.6 would give you decent sharpness with that lens, but focus is important. How did you focus the sample shot?
I used single focus (i think its called, sorry only just started photography) focused on his eyes and then re-compossed the photo with the shutter half pressed.

03-19-2016, 11:40 AM   #5
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QuoteOriginally posted by jatrax Quote
Manual focus or auto?

If manual check your diopter setting.

If auto do an autofocus test using a tripod and a focus test target to rule out front/back focus which needs adjustment.

Also what aperture are you using? At f/1.8 your depth of focus might be too small increase the aperture and try again.

At very small apertures even a slight movement as you press the shutter button can cause your focus to be off so check your stance and holding/breath control.
It is autofocus think I was shooting at 1/250 with the aperture set at f5.6
03-19-2016, 12:01 PM   #6
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Is your camera set to AF.S or AF.C?
If it's in AF.C then it will refocus when you recompose.

If it did refocus, then I'd bet that a portion of the bottom of his shirt or jacket is sharp.
03-19-2016, 12:25 PM   #7
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QuoteOriginally posted by jaremart Quote
Is your camera set to AF.S or AF.C?
If it's in AF.C then it will refocus when you recompose.

If it did refocus, then I'd bet that a portion of the bottom of his shirt or jacket is sharp.
AF.S as I understand AF.C is continuous?

---------- Post added 03-19-16 at 12:27 PM ----------

Also, off subject, when I am zooming in 1:1 in lightroom It is introducting noise into the picture. Is this normal?
03-19-2016, 12:34 PM   #8
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QuoteOriginally posted by Suarez Quote
AF.S as I understand AF.C is continuous?

---------- Post added 03-19-16 at 12:27 PM ----------

Also, off subject, when I am zooming in 1:1 in lightroom It is introducting noise into the picture. Is this normal?
the noise is because it is shot at iso 800. k3 is good but you will still need to adjust in lightroom, also if you raise the exposure in lightroom, even at a lower iso, you will add noise. the noise reduction settings should be useful removing some of it.

I struggled with focus when I first got the k3, and learned that it is very sensitive to motion, so I really have to make sure my shutter speed is much higher than I am used to using

edited: I just read you are are using k5, and your shutter speed seems good, so it may be auto focus issue. but the iso and noise issue still applies.

03-19-2016, 12:40 PM   #9
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+ 1 to what murfy said. Also, if you zoom in on your image, any noise that is there will be more pronounced / easier to see.
03-19-2016, 12:42 PM   #10
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QuoteOriginally posted by Murfy Quote
the noise is because it is shot at iso 800. k3 is good but you will still need to adjust in lightroom, also if you raise the exposure in lightroom, even at a lower iso, you will add noise. the noise reduction settings should be useful removing some of it.

I struggled with focus when I first got the k3, and learned that it is very sensitive to motion, so I really have to make sure my shutter speed is much higher than I am used to using

edited: I just read you are are using k5, and your shutter speed seems good, so it may be auto focus issue. but the iso and noise issue still applies.
Maybe I was a bit naive, when I read that ISO shouldnt really matter around that sort of setting, but definitely lightroom is making it better
03-19-2016, 12:44 PM   #11
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Here is another example
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03-19-2016, 12:49 PM - 1 Like   #12
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QuoteOriginally posted by Suarez Quote
Maybe I was a bit naive, when I read that ISO shouldnt really matter around that sort of setting, but definitely lightroom is making it better
it does. do a few test, shoot at 100 iso with a flash or good sunlight and exposure. then shot 100 iso underexposed by 2 or more shots and raise the exposure in lightroom. You will see noise, even at 100

This will be more pronounced at 800. digitial sensors are good, and much better than film, but you still need to get the exposure correct. if you shot at 800, its best not to underexpose. If I shot at 800 or above, I tend to overexpose slightly by a stop or two.
03-19-2016, 12:52 PM   #13
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How close are you to the subject? Is the image cropped? At F 5.6 I would think the eyes would be in focus so I don't think it is your settings. If you want an easy way to see if it is your lens focusing, check this video
There are people on this forum who can help

Randy
03-19-2016, 01:30 PM   #14
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QuoteOriginally posted by slip Quote
How close are you to the subject? Is the image cropped? At F 5.6 I would think the eyes would be in focus so I don't think it is your settings. If you want an easy way to see if it is your lens focusing, check this video https://m.youtube.com/watch?v=7zE50jCUPhM
There are people on this forum who can help

Randy
Er, not sure, about 10-12 feet I think? Maybe less?

No, I dont like cropping my images, where I can help it, for that reason. f5.6 does seem to be round about the sweetspot for that lens.

---------- Post added 03-19-16 at 01:34 PM ----------

QuoteOriginally posted by slip Quote
How close are you to the subject? Is the image cropped? At F 5.6 I would think the eyes would be in focus so I don't think it is your settings. If you want an easy way to see if it is your lens focusing, check this video https://m.youtube.com/watch?v=7zE50jCUPhM
There are people on this forum who can help

Randy
I also saw 'fine-tuning' Option through the menus, I dont know enough about this. If i increase this to the maximum (+10) will this incresase the sharpness of the photo's. Any disadvantages to tuning it so high?
03-19-2016, 01:49 PM   #15
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QuoteOriginally posted by Suarez Quote
Er, not sure, about 10-12 feet I think? Maybe less?

No, I dont like cropping my images, where I can help it, for that reason. f5.6 does seem to be round about the sweetspot for that lens.

---------- Post added 03-19-16 at 01:34 PM ----------



I also saw 'fine-tuning' Option through the menus, I dont know enough about this. If i increase this to the maximum (+10) will this incresase the sharpness of the photo's. Any disadvantages to tuning it so high?
If you don't want to dot tune your focus you can first take a shot on something that is close to horizontal let's say an acorn on a walkway around 15 feet away. Make sure you have a narrow field of view (lens lowest F stop) Take several shots. The adjust it to around -5 and try the original shot out again. Play with the settings until you get that subject dead sharp.
You can't mess it up as you can put the camera back to zero.
Let us know how you do

Randy
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