D7000 Focus Fine Tuning - Zoom Lens
/forum/topic/1152225/1

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workerdrone
Registered: Dec 29, 2010
Total Posts: 1124
Country: United States

Motion blur possible on a 300mm shot at 1/400th? absolutely. And the D7000 is not an easy camera to shoot pixel level sharp pix with, leading to many users complaining - but what it comes down to is they're complaining about the high resolution of their camera exposing their less than ideal shooting technique for the first time.



blutch
Registered: Jul 29, 2012
Total Posts: 807
Country: United States

I'm completely in belief that it is my technique. I have been working on it. But.. I don't know what else to do. I really need some suggestions on how to control this better. Help?

B



paparazzinick
Registered: Jan 08, 2005
Total Posts: 7389
Country: United States

tmak54952 wrote:
Just starting to fine focus my lens on the D7000, With the zoom lens, where (FL) do you fine focus. . . mid range or perhaps at the FL you use the most?


when i tune a zoom lens i test it at max then widest and then in the middle. most of my zooms they were all similar on where the adjustment needed to be. On one lens, it was -10 at max, -7 at wides and -8 in the middle. I ended up doing -8 and retested. It was not 100% perfect but it was better than before.

Someone made the comment on just calibrating on the longest focal length. Well if you do that and then only use the longest focal length then why not just get a prime?



workerdrone
Registered: Dec 29, 2010
Total Posts: 1124
Country: United States

well, good handheld technique is a lot like shooting a rifle well - support the camera well, gently squeeze the shutter, don't stab it, so that you almost don't know exactly when it's going to go off even though you do mean to trigger a shot. Often shooting bursts will give you a shot in the burst that happens to be much sharper, and you can toss the rest...

dial up the iso as needed to get sufficient shutter speed - say at least double the focal length unless you can reliably do better. If you're still getting motion blur at 1/1000 on that 300mm then Houston, we have a problem :-)

and use a monopod or tripod whenever you can. I'm guessing many of the shots you admire have been taken using a tripod.



blutch
Registered: Jul 29, 2012
Total Posts: 807
Country: United States

Thanks WD. I am an experienced archer and rifle, handgun shooter. The similarities are many. I tried it out handheld tonight and got good results with bursts for sure. I wish this thing had VR.

B



Red Rover
Registered: Jul 13, 2012
Total Posts: 230
Country: United States

Here is a good explanation of AF and a simple to use focus chart. You don't have to make this a real complicated test.

I used this to determine that my 17-55 was still back focusing even when adjusted to -20. I took them in to a Nikon Repair Center and they agreed that the camera/lens was still back focusing and needed callibrating. Unfortunately, the D7000 needed a part for another issue and they still haven't received it from Nikon so I don't have the recallibrated camera and lens back yet.

http://focustestchart.com/focus21.pdf



blutch
Registered: Jul 29, 2012
Total Posts: 807
Country: United States

Ok. I finally had a chance to try this chart with my D7K and a nikkor 17-200 VR. This is the result at 200mm focal length. If you look close, NONE of it is in focus. I used a good tripod, flash, 1/200th and a remote control shutter. Any thoughts/ideas on this one? B


121018-0045-3.jpg by blutcherama, on Flickr



blutch
Registered: Jul 29, 2012
Total Posts: 807
Country: United States

If you zoom in on the words on the sides, none of them are in focus... hrmmmmm. I did it four times and they all look like this.



Gregstx
Registered: Dec 07, 2010
Total Posts: 590
Country: United States

blutch on your example of shooting with your 300 mm lens at 1/400th. Your 300 mm lens on your D7K is the equivalent of a 450 mm lens. At 1/400th you are shooting at a slower shutter speed than would have been recommended back in the old days. And on my D7000, I am adding a little extra in to make sure I'm good. Maybe 1/500th or faster, light permitting. On shooting the focus chart, I would suggest you try shooting it in the Live View mode. See is the results are the same.



blutch
Registered: Jul 29, 2012
Total Posts: 807
Country: United States

I am having much better luck with the 300mm after fine tuning it. (+15.) Plus, I'm using a monopod with it pretty much all the time. It has improved my keeper rate considerably. I will go shoot a couple in Live view mode with th 18-200. I'm not sure why though.... Can you elaborate? Thanks! B



blutch
Registered: Jul 29, 2012
Total Posts: 807
Country: United States

Ok.. I also realized i was way underexposed on that last test.. So, I did it in live view and the exposure is better.. I think. Using the on-camera flash with diffuser. This is considerably worse than the previous test. Nothing is in focus.. I don't get it.


121018-0046.jpg by blutcherama, on Flickr



M635_Guy
Registered: Dec 22, 2010
Total Posts: 2291
Country: United States

I hate asking a stupid question, but did you turn VR off?



blutch
Registered: Jul 29, 2012
Total Posts: 807
Country: United States

uh oh. ... nope. I will redo it later tonight. Thanks for remembering that.

B



blutch
Registered: Jul 29, 2012
Total Posts: 807
Country: United States

Ok. Here it is without VR. I don't see any big difference. I can't help but think I'm doing something wrong here with the test. Can someone give me advice on the exposure? I'm at 1/60 F5.6 and iso 1000 with on camera flash with a puffer/diffuser and an overhead ceiling light in the room. This lens has produced sharp photos, but perhaps not at its full focal length?


121018-0047.jpg by blutcherama, on Flickr



workerdrone
Registered: Dec 29, 2010
Total Posts: 1124
Country: United States

@blutch didn't you read the instructions I left earlier - that's really all there is to it - why are you shooting a 200mm lens at 1/60th sec, and with a flash? Why are you at iso1000 and using artificial light?

Set it iso200 (base for D7k, right?), get rid of the flash, make sure the camera is rock solid, VR off, lens wide open, don't worry about the shutter speed, and focus live view to see what that camera / lens combo is actually capable of. Stop down a couple stops to see if it gets sharper (but not to test AF)

In your last two pictures the FOCUS looks pretty much on. (At zero). If you're looking for pixel level sharpness from your great sensor, maybe your lens just isn't up to the task and you are only driving yourself nuts trying to turn a $500 lens into pro glass with testing.



blutch
Registered: Jul 29, 2012
Total Posts: 807
Country: United States

Hehehehe.. you are right.. didn't follow directions... thanks for the reminders.. will do. Everything is fuzzy when I enlarge.. but I realized that it is a ink jet printer and it is just plain fuzzy around the edges of the print. Duh. I did this with my 50mm 1.8 and my 300mm F4 and got similar results. Will try it at base iso. Exposure doesn't matter? what do you set the shutter at or do you just use auto? I have never used Live View, so I'm fairly clueless on how to use it and what the purpose is.. I noticed there was no exposure meter.. maybe that's a clue? B



blutch
Registered: Jul 29, 2012
Total Posts: 807
Country: United States

WD - i realize the confusion now. I fine tuned my 300mm f4 using your method. It worked great. I am getting very sharp photos with that lens now. Then on another thread I read about this chart, so I downloaded it and decided to try to fine tune my zoom with it. I meant to post it to THAT thread, but posted it to this one instead. Duh. I can't even find that other thread now. Sorry about that. I still would like to know what is different about using liveview for this. B



Gregstx
Registered: Dec 07, 2010
Total Posts: 590
Country: United States

You can get some camera movement due to mirror slap, even on a tripod. That is why I suggested using Live View. When the D7K first was introduced a lot of folks commented that they got sharper test photos by using LV. I have an extremely heavy tripod that I used to use when I shot with a huge Betacam pro video camera. And under some conditions, I still can detect mirror slap induced movement on that heavy tripod.



workerdrone
Registered: Dec 29, 2010
Total Posts: 1124
Country: United States

@blutch, using live view, magnified view, on a tripod, and manual focusing on a tripod is really the only way to ensure perfect focus and either get optimum results for slow, deliberate shooting, or to test to see how sharp your lens really is.

Using live view and AF actually uses a completely different AF system in your camera and should also be very accurate. But again, it's slower.

Viewfinder AF is very fast but can need tweaking (fine tuning) with different lens/body combos to get it dialed in. Even then it won't be as reliable as live view focusing. But tuning can dramatically increase your keeper rates with fast lenses. The fine tuning doesn't affect the live view focusing, only the viewfinder focusing.

You could also have perfect focus and still get unsharp images due to camera shake, a poor lens copy, dirty or damaged lens, etc. You're also introducing a printer into the equation now. So many variables....the important thing is to enjoy the hobby, improve your skills, and try not to obsess too much over the gear itself or endless testing :-)



workerdrone
Registered: Dec 29, 2010
Total Posts: 1124
Country: United States

Gregstx wrote:
You can get some camera movement due to mirror slap, even on a tripod. That is why I suggested using Live View. When the D7K first was introduced a lot of folks commented that they got sharper test photos by using LV. I have an extremely heavy tripod that I used to use when I shot with a huge Betacam pro video camera. And under some conditions, I still can detect mirror slap induced movement on that heavy tripod.


I remember mounting a 70-200VR1 on my D7k and setting the combo on the countertop to take some shots across the room, triggered by self timer, and being shocked how crappy they were. Unusable from mirror vibration, when the camera was rested well, or so it seemed.



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