lens focus problem

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R

realspeed

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I have done some tests with strange results. What I did was with the Nikon D810 with the Nikon24-70mm f2,8G @70mm on a sturdy manfrotto 055x Prob tripod and Manfrotto pistol grip head. Absolutely rock solid. I attached a wired remote trigger release to stop and camera shake and an HDMI cable to the monitor. Outside at 11ft away approx I set up a Spiderlenscal target.

Ok lined everything up set the camera to Aperture Priority- auto ISO- spot metering @f2.8 at 70mm on the lens, ready now to test. Got the target up on the rear camera screen and also on the monitor, the picture could not be sharper, so took the picture via the remote switch. The picture reviewed straight away on monitor and rear screen and after camera using off/on switch, and enlarged the photo with the 4 way switch camera button and the photo badly out of focus. tried this several times with the same result. tried with fine tune on and off still the same O F F
even viewed via computer no difference
First though shutter slap so did same in quiet mode with same result, so that wasn't the cause

OK camera or lens was my next question. So tried the same with my Nikon 70-200 f2.4 G lens @70mm everything set up the same. Ran exact same test and same view check after photo taken and the picture was pin sharp. That eliminated any camera mirror out of alignment also the camera processing is ok.

So it has got me beat, so sod this for a game of playing silly buggers so ordered the tamron then will send the lens for an over haul. What I can't get my head around is the initial setup the picture was sharp the resulting photo wasn't.

Any ideas?
 
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What focus mode were you in? When I do sharpness tests I always use mirror up which helps minimize mirror shake. I also never use any auto features, it's full manual or nothing unless I'm doing an AF calibration in which case I'm in single servo center point AF. It sounds like you saw the lack of sharpness when you enlarged the photo. If the entire frame is soft it likelt isn't a focus issue. I'm not familiar with your target, but there should be some part of it in focus if it is just an AF fine tune issue.
 
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THis was the standard AF test in Aperture priority usually used for fine focus adjustment. the final photo was all OFF over the whole picture. The other lens same test was sharp
 
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I would check to make sure that VR was set to OFF on both lenses during both tests. Maybe VR was ON for you 24-70mm and OFF for the 70-200mm? And I would make sure that no filters are on either lens.

I doubt if this is a factor, but you may want to set back button focusing with the AF-ON button. This eliminate any chancethat the lens could perhaps refocus when the shutter is tripped.

Just rerun all the tests to see what happens.

Like you I am puzzled with the results.
 
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Many lenses are quoted as f14. 2.8 etc but the image quality at max aperture is rubbish. I would try setting the FFA at f 5.6 and if its off the scale send it back . If its ok then you could send it back as a bad copy ..not sure if its new or second hand.
 
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Near me is a small workshop dedicated to camera and lens repairs. Thjey don't sell stuiff and going there is like a step back in time. Used them several times and get a warranty on their work for 6 months. The workshops were farm outbuildings now housing different businesses.
No flash smart arse sales kids who know nothing, just two guys who know their jobs, One does camera repairs and the otrher on lenses
 
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