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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

sharpness issues? (1 Viewer)

It's also worth checking your camera/lens combo for Front/Back focusing issues.

How do you check for this?


Here's a sample focus test. This one's not really the best, because the focus target in the center (the wider black bar) is not parallel to the sensor, so there's some front/back error possible just in how the autofocus interprets the object. A better target is a separate object, set up parallel to the sensor. You get the idea, however. The paper was set up at roughly 45 degrees.

I think it's also a good idea, not followed in this example, to set up your focus test at about the distance you normally use the lens, since it's possible for the lens to have front focus at one distance, and not at another.

Some Nikon DSLR's have a fine-tune focus adjustment, so you can take a series of shots like this one, and tweak your lens/camera combo.

I hope the image comes thru,

Jim
 

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Marcel, I shoot with a 70-200 and a 1.7 TC,, using a D300,, I am an (aged) astronomer and have always tested all my lens for critical sharpness,, my 70-200 was almost dead on but with the TC 1.7 behind it the camera needed a +5 for fine focus set up,, for my test I do all comparisons at 200 to 300 increase so you can really see what is sharp or not,, also test the lens at different distances,,

even the best lighting condition cannot overcome a lens that is just a tad OOF,, would certainly recommend you assure the lens and body combination are correct before starting other testing,,


Derry
 
Are you locking the mirror up prior to taking the shot? If not the mirror flipping up just before the exposure will cause camera shake...only minutely but enough to be noticed in the shot.
 
no I just take the shot, been trying over the weekend but most shots are unsharp. excuse my ignorance but what is mirror lockup and how does it work.
I used remote control (wireless) for my nikon, but you are right as soon as the mirror clicks, there is vibration on my D2X. can you explain mirror lockup?
marcel
 
Not sure how it works on the D2X but it should be similar to a D3, on a D3 the mode dial on the left of the body has an option in with the High/low speed continous shooting called Mup, You set that and then when taking a shot the first press of the shutter locks the mirror up and you then have to press the shutter a second time to actually take the picture.........but as the mirror has already been locked in position there is no shake from the mirror flipping up :t: Normally with the longer lenses when you take a shot on a tripod the mirror flipping up causes vibrations to travel down the lens and back up to the camera body causing a small amount of camera shake.

The other option you have is the long lens technique;

http://www.moosepeterson.com/techtips/longlens.html

Better than how I can describe it.
 
that,s a great find, thanks!!
made some close ups geese , just but still quite grainy at 400 iso
 

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Marcel,

Stupid question, is your VR off when you shooting off your tripod?? Not sure if it has an influence, but worth checking.

Regards,

Leon
 
another foto taken from @ 20 meters
shot in large jpeg and resized
F8 1/1000
iso 400 focal lenght 420 mm
spot metering aperture priority
EV 0 AFC shot from tripod, remote control trigger, VR Off.

still find it not sharp, used long lens method, weather dull/overcast
 

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This still looks pretty good to me. Are you printing or just viewing on your monitor ar 100-300%? A 12mp-sensor image should not be evaluated onscreen at more than 50%. Your monitor just does not have the resolution capability.

Also Nikon's default jpeg is soft. You need to apply sharpening in camera. Not sure how its done on yours, but on the D90 it is done with Picture Controls.

Rick
 
To me, 20m is to far to get any sharpness out of something like this (mostly white), combined with dull overcast weather, you have no chance whatsoever. Light is everything.

Personally, I have come to the conclusion, that anything further than 5m - 7m for birds is a stretch. And, most of the time we are applying heavy crops to get anything out of the pic.

Its difficult, but you must keep on shooting until you find the happy medium. I am also starting to use bracketing to try and get my exposures better.

All the best.

Leon
 
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