D70 Focusing Woes

Matt Grunau

Matt Grunau

Adobe Demigod
Hi all. A few months ago I dropped my camera about 2 feet. it landed mostly on my foot, and was in tall grass. I took it inside imdeiately and snapped off a few just to make sure it was ok. Sure seemed to be.


Lately though, I have been having one hell of a time getting a subject in complete focus. When I took pictures of the moon, for instance with a 300 mm lens, I turned it to infinifty, and then actually went a little further and blurred out. I had to manually back outabout 3degrees per pic to get a couple that were in focus.

Not I take pictures of my son, and he is rarely in focus. I do use the autofocus, since I dont have one of those cat's eyes things. Take a look in the last page of the Nikon thread and you will see four examples. All four were taken at around 3, dun behind, so plenty of light, with the 55mm Nikor 1.8. I just fathom what I am doing wrong.

Is it possible that I am shooting underlight even though it looks fine to me and getting a bit of motion blur? Even at 125th a second on a non moving target?

You will also notice from those pics the depth of field is incredibly short, the tip of his nose is in focus (well, as much as they can be) and his eyes are out of focus. What would cause this? I have a 28-80 kit lens, a 300mm kit lens, and my Nikor 55 mm 1.8 (or is it 1.6?? Cant remember)

I just want to take a crisp picture, and I cant get it even in what looks like should be to me more than adequate lighting.

Is there a focus chart I could hit with something like one of my 500 watt fresnels as a bench mark?

Any help would be appreciated.
 
Thanks Jeremy. I think the problem is Shooting in poor light with bottom level lenses.

I gave it another go today, pointed at a lam with a 60 watt bulb, and the image came out fine.

Strange though, even with my Nikor 55, pointing out the window at deer in full sunlight is giving me 250th of a second, but with the apature at 1.6. anytime I take indoor photos, even with all the lights on, I am prompted to use the flash.

and If the apature is 1.6, is that going to give me very shallow depth of field?

just damned odd. It's almost like the camera is in perpetual low light mode, even when there is plenty of light.
 
the pics you posted of your boy looked fine to me. The areas that were in the focus area were spot on. If you are shooting at f/1.8 and you are that close to the subject, the DOF can be less than an inch sometimes.

I don't have my camera with me right now, but I've taken pictures of the keys on my computer keyboard with my 50 f/1.8 and I can focus on just one letter on a key with all other being out of focus.
 
DivotDan said:
the pics you posted of your boy looked fine to me. The areas that were in the focus area were spot on. If you are shooting at f/1.8 and you are that close to the subject, the DOF can be less than an inch sometimes.

I don't have my camera with me right now, but I've taken pictures of the keys on my computer keyboard with my 50 f/1.8 and I can focus on just one letter on a key with all other being out of focus.
Click to expand...

THanks Dan. What would you suggest to get less DOF? When I crank up the iris to try and rid it, the shutter speed goes down faster than my sister on a weekend.


Maybe I just have really crappy lenses.
 
An f/1.8 or f/1.4 lens is what it is. The only 55mm I know if is a f/2.8 micro. I've never played with it but I know that most Nikon primes regardless of age are clear crisp lenses. My first suggestion with this lens would be make sure focus is on the eyes and not just whatever is in focus brackets. Second would be to backup a little bit. This will help increase the perceived DOF, and you can always crop it later if you need to.

That said, you can most likely afford to close the iris down a little. If I'm having issues with focus then I usually knock down to 2.3 or 2.8 and bump the ISO to 400ish. The noise shouldn't be much of an issue with that much light still coming in. Whatever you do, don't dump your glass. Just learn how to make it be your friend (ala Bob Ross)


Here is a few examples I took of my nephew with my 50mm f/1.8. I bumped the aperture up to f/2.8 on the first one ISO 100. On the second I shot at f/1.8 but ISO 400.
 
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The whole focusing to infinity thing shouldn't be relied on. Because it is almost impossible for camera/lens manufactueres to get the backfocus distance of the lens to the sensor plain perfect, most lenses will focus past infinity. You have to use your eye when trying to focus at something like the moon.
 
DivotDan said:
An f/1.8 or f/1.4 lens is what it is. The only 55mm I know if is a f/2.8 micro. I've never played with it but I know that most Nikon primes regardless of age are clear crisp lenses. My first suggestion with this lens would be make sure focus is on the eyes and not just whatever is in focus brackets. Second would be to backup a little bit. This will help increase the perceived DOF, and you can always crop it later if you need to.

That said, you can most likely afford to close the iris down a little. If I'm having issues with focus then I usually knock down to 2.3 or 2.8 and bump the ISO to 400ish. The noise shouldn't be much of an issue with that much light still coming in. Whatever you do, don't dump your glass. Just learn how to make it be your friend (ala Bob Ross)


Here is a few examples I took of my nephew with my 50mm f/1.8. I bumped the aperture up to f/2.8 on the first one ISO 100. On the second I shot at f/1.8 but ISO 400.
Click to expand...


Thanks for the adivce. I will try those. And your nephew and my son look like they could be brothers. Cool. Especially the eyes.
 
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