Focus - Camera or User Error

PhilD41

So I have been playing with my new lights (Wow have I got a lot to learn!!!) and kept running in to focus issues. Mainly, I would snap a photo and realize my daughters ear was very sharp, but her face was not. I usually adjust my AF point manually to match the composition and try to snap the photo directly after acquiring focus lock. To be honest, I have been having issues for a while with focus and things seemed to get a little better when I started focusing on the kids noses instead of their eyes.

The image below was taken about a meter from the subject with the AF point on my D7000 square on her nose. Even with that, I backed off a few mm after acquiring lock. Finally, the eyes are in focus (pretty much).

Camera: Nikon D7000
Exposure: 0.004 sec (1/250)
Aperture: f/2.2
Focal Length: 50 mm
ISO Speed: 160

So, after researching on a way to "adjust" my older Nikkor AF 50mm 1.4D I ran into all sorts of horror stories about the D7000's AF. So the question I have to figure out, is it the camera or driver error? I am by no stretch of the imagination a pro, but I thought I knew what I was doing with this camera. Any good tests you can suggest? I am planning on doing the same thing with my 18-55mm lens, but at F5.6 it is hard to get anything out of focus.

dlscott56

I'm using a D7000 as well and only have focus problems when using an old cheap lens I have that gave me trouble on my D80 as well. I'd suggest reading http://regex.info/blog/photo-tech/focus-chart and printing out the chart. Then take a couple of quick tests. Remember to use a tripod for the test. There are other systems you can purchase to test and adjust focus but this may be a good start.

dlscott56

By the way, make sure you reset any adjustments you've made in the AF fine tune area, or turn AF fine tune off, before doing the test to see where your base line is.

PhilD41

Thanks Dave, I will definitely give that a test tonight. By the way... I went looking for the AF fine tune area on the D7000 and never did. Does it have one?

dlscott56

PhilD41 wrote: »

Thanks Dave, I will definitely give that a test tonight. By the way... I went looking for the AF fine tune area on the D7000 and never did. Does it have one?

Yep, it's in the setup menu. Second to last item right above Firmware version.

Icebear

It would be helpful if you'd include your Exif data. Flickr shows f/2.2, and you say your subj dist was about three feet. At your focal length of 50mm, you have about one inch DOF. That's roughly 1/2" in front and 1/2" behind the tip of her nose, if indeed that's where you focused. Her eyes are already going soft to my eye. If you want crisp eyes, you'd best put your focus point on the eye, not the nose. And at f/2.2, your subject needs to be pretty much dead square to the camera or you will only get one eye in focus. Shooting portraits at f/2 is a highly specialized technique, and IMO seldom successful. Stop it down. You'll be happier with your results. You can't fight physics.

Hackbone

I'm not a Nikon guy but on Canon you can reset one of the buttons function to focus and hold it and then repositon and use the traditional shutter release to capture the photo. I would think that Nikon can do this also. It really helps to shoot that way but takes a short while to get used to it.

PhilD41

Icebear wrote: »

It would be helpful if you'd include your Exif data. Flickr shows f/2.2, and you say your subj dist was about three feet. At your focal length of 50mm, you have about one inch DOF. That's roughly 1/2" in front and 1/2" behind the tip of her nose, if indeed that's where you focused. Her eyes are already going soft to my eye. If you want crisp eyes, you'd best put your focus point on the eye, not the nose. And at f/2.2, your subject needs to be pretty much dead square to the camera or you will only get one eye in focus. Shooting portraits at f/2 is a highly specialized technique, and IMO seldom successful. Stop it down. You'll be happier with your results. You can't fight physics.

Exactly! Somewhere around 1.25" from my calculations. I wanted a shallow DOF so I knew where it was focusing at. When I focused on the eye, the only things in focus were the ears (both of them). Even focusing on the nose, I believe the true focal point is just behind the eyes. I don't usually shoot portraits at f/2 either, but on a crop sensor it isn't quite as bad as it would be on, say the D700 or so. Sorry, I didn't realize the EXIF date was removed when embedding from Flickr. I added it above.

Hackbone wrote: »

I'm not a Nikon guy but on Canon you can reset one of the buttons function to focus and hold it and then repositon and use the traditional shutter release to capture the photo. I would think that Nikon can do this also. It really helps to shoot that way but takes a short while to get used to it.

Yep, Nikon can do this as well. Doesn't help much if what I think I am focusing on isn't, or with a really narrow DOF. I am still not 100% sure it isn't me, but I am really start to believe it isn't. Tried a few more shots with my son and still had to back off after focusing to catch the eyes.

dlscott56 wrote: »

Yep, it's in the setup menu. Second to last item right above Firmware version.

Thanks! Found it. Not sure how I missed that. Unfortunately my printer won't print when it thinks it is out of toner so I can't print the focus test. I have new toner arriving on Monday so I will give it a go then. I am very curious to see the results. I should be able to check across all my lenses with that as well.

WingsOfLovePhoto

Using studio lighting is a bit different with settings than with ambient light. Most studio photographers will shoot f8 or higher. with an ISO of 200 and a shutter speed of 1/200th. With the settings you are using you will have some trouble focusing the whole face. I am a huge stickler for sharp focus. I am always on single focus mode (Nikon) Could you be on the continuous mode? That will make an movement in the subject change your carefully selected focus. With single subjects that are basically static and using lighting that will cause a stop motion you wouldn't need continuous mode. I always put my single focus point right between the eyes and remember the rule of focus. 1/3th in front and 2/3rds back will be in focus. you can experiment with your position rather that your settings to get the blur, but also remember this will probably cause some distortion of the face. Let me know your thoughts on this..I've been a Nikon girl for a long time :-)

Sam

Phil,

Try this: Set a ruler up at a 45 degree angle. Put your camera on a tripod and use a remote switch.

Focus on the 6 inch mark, try both manual and auto. Do a set of say 3 to 5 to get an average.

Use a variety of f stops. This will allow you to see if your camera is front or back focusing.

Sam

PhilD41

Sam wrote: »

Phil,

Try this: Set a ruler up at a 45 degree angle. Put your camera on a tripod and use a remote switch.
Focus on the 6 inch mark, try both manual and auto. Do a set of say 3 to 5 to get an average.
Use a variety of f stops. This will allow you to see if your camera is front or back focusing.

Ah, a ruler would work. I have a date with the wife this evening, but tomorrow I will be doing this with either a ruler or the focus test page provided above. I am pretty sure there is an issue, as I have adjusted the fine tune to -20 and now things are much closer.

WingsOfLovePhoto wrote: »

Using studio lighting is a bit different with settings than with ambient light. Most studio photographers will shoot f8 or higher. with an ISO of 200 and a shutter speed of 1/200th. With the settings you are using you will have some trouble focusing the whole face. I am a huge stickler for sharp focus. I am always on single focus mode (Nikon) Could you be on the continuous mode? That will make an movement in the subject change your carefully selected focus. With single subjects that are basically static and using lighting that will cause a stop motion you wouldn't need continuous mode. I always put my single focus point right between the eyes and remember the rule of focus. 1/3th in front and 2/3rds back will be in focus. you can experiment with your position rather that your settings to get the blur, but also remember this will probably cause some distortion of the face. Let me know your thoughts on this..I've been a Nikon girl for a long time :-)

Thanks for a starting point on the settings. I have managed to get close to this with just trial and error. This was at 1/250, but that is the top most range for flash sync on this camera. From my calculations, f/8 would give me about 12" DOF. Probably much better for a traditional portrait. I will practice with that some. I have spent the last year without flash or lights and am not use to being able to use the higher apertures without having to really crank the ISO.

Yes, I almost never leave single focus on the Nikon. I like to know and control where the focus point is. I know people always say to focus in front, but didn't know it was split 1/3 by 2/3. I will keep that in mind now though. I am not sure what you are saying will cause the distortion though.

In general, I would like to say thanks to everyone. I am quite the fledgling hobbyist, with the grand plan to someday at least have my hobby pay for itself. I appreciate the time taken to help me and others out.

WingsOfLovePhoto

Yes, I almost never leave single focus on the Nikon. I like to know and control where the focus point is. I know people always say to focus in front, but didn't know it was split 1/3 by 2/3. I will keep that in mind now though. I am not sure what you are saying will cause the distortion though.

Single focus gives you much more control than continuous focus. You just move the "single" box to between the subjects eyes. (not always center... just where ever you need to move it to get close) It gives you total control over the focus. Give it a try. On your nikon choose the s instead of the c and change your other setting to single rather than dynamic focus... can't hurt to try :-)

PhilD41

WingsOfLovePhoto wrote: »

Single focus gives you much more control than continuous focus. You just move the "single" box to between the subjects eyes. (not always center... just where ever you need to move it to get close) It gives you total control over the focus. Give it a try. On your nikon choose the s instead of the c and change your other setting to single rather than dynamic focus... can't hurt to try :-)

Okay, I think we must missed each other there I use AF-S almost exclusively as well. Just dial the little box around where I want it before taking the picture. As fancy is the auto and 3D is, it never pics the exact same spot I want it to.

PhilD41

So here is the results of my test. Pretty safe to say there is a focus issue. However, I am thinking it is the lens, not the camera as I feared. Below is a photo of the focus test without any compensation on the 50mm 1.4D. EXIF should be in the images if you are curious.

As you can see it is pretty bad back-focused! That explains a lot to be regarding how hard of a time I have had getting proper focus! So, I put in a full -20 compensation in the camera and got the following.

It isn't perfect, but at least the line I am focusing on is actually in focus. I can live with this for now and it should help out my portraits quite a bit! When I improve some I may want to look at replacing this lens. Anyway... Fearing it may be an issue with the camera I put on my 18-55mm set to 55mm and tested it. Below is the zero compensation image.

It still has a slight back-focus issue, but only took about -5 clicks of compensation to correct. I will test my 70-300mm sometime as well one of these days. The fact that the 18-55mm was so much better than the 50mm makes me think it is more an issue with the lens then camera. I bought the lens used and who knows, that might be why it was being sold. Now that I know, I believe I can correct for it and still move forward without too much frustration.

What do you all think? Is this a correct conclusion or am I missing something somewhere? I don't mind sending the camera back to Nikon, but I right now I have talked myself out of it being a camera issue.

Icebear

Just curious why you didn't do your focus test with your 50mm at f/1.4? I'd have thought that the shallowest DOF you could get would have been preferable, no?

Sam

Phil,

Looks like you set to go take photos!

Don't worry about needing more compensation on one lens versus another. It's all about tolerances. If the lens it at one end of the mfg tolerance, and the camera at the opposite end of their tolerance level you would need additional compensation. No worries.

Sam

PhilD41

Icebear wrote: »

Just curious why you didn't do your focus test with your 50mm at f/1.4? I'd have thought that the shallowest DOF you could get would have been preferable, no?

Probably would have, although I have read some cases were the changes based on aperture. I rarely shoot wide open so I left it where I was trying to take photos and failing. But yes, it would be the easiest way to see the issue. I may do it wide open just for fun.

Sam wrote: »

Looks like you set to go take photos!

That, sir, is exactly what I was thinking!