Not impressed with new prime lens. Am I doing something wrong?

[480sparky]

This is exactly what I do with all my lenses. I know where the 'sweet spot' is for each one, and if it's a zoom that spot may change over the focal length change.

Which is why it's such a shame that the D3x00 and D5x00 series can't fine-tune autofocus.

The 'sweet spot' has nothing to do with auto-focus.

 

[daggah]

DxOMark doesn't do real world tests?

Unless you consider shooting test charts to be the epitome of your photography skills...no, they don't. That's why you don't get sample images. Hell, in the 35 1.8's case, they don't even rate it at all for travel usage, and that's usually when I use it.

 

[daggah]

The 'sweet spot' has nothing to do with auto-focus.

Sure it does. You'll never find it if your lens and camera combo has front or back-focusing issues, and you can't fix those on lower end DX DSLRs.

 

[pgriz]

Daggah, usually the "sweet spot" refers to the aperture (or small range of apertures) where the lens sharpness is at the maximum. For primes, that is relatively easy to figure out, as you do a series of exposures varying the aperture through its range. Focusing for these kinds of test is always manual, and usually using some kind of focusing assist (such as the 10x magnify on live view). IS/VR is switched off, as is AF. Then it is possible to examine the images at each aperture and see where in the aperture range the sharpest images lie.

With zooms, this is more complicated, and the same sequence of tests (minimum through maximum aperture) are done at several focal lengths. The sweet spot that Sparky refers to IS dependent on the focal length, and it does happen that the aperture at which you get maximum sharpness varies as you go through the focal length range.

AF, and the issues of front/back focusing is something else, and the focusing can be adjusted by the user or some camera models, but require a trip to the service center for others. I have a Canon T1i which had some back-focusing issues, and after I sent the service center the images documenting this, they asked me to sent the camera in for adjusting. Now the auto-focus is much closer to where it needs to be, but is not perfect. S'ok. I know what I can shoot with AF and where I need to go to manual focus with the focus assist.

 

[480sparky]

The 'sweet spot' has nothing to do with auto-focus.

Sure it does. ...........

You've been misinformed then.

 

[Robin_Usagani]

The camera will always AF with the lens wide open. The aperture gets smaller only when you press the shutter.

The 'sweet spot' has nothing to do with auto-focus.

Sure it does. You'll never find it if your lens and camera combo has front or back-focusing issues, and you can't fix those on lower end DX DSLRs.

 

[480sparky]

The camera will always AF with the lens wide open. The aperture gets smaller only when you press the shutter.

Or press a DOF Preview button.

 

[bhop]

...I'm noticing at least 8 out of 10 pictures taken with this lens come out blurry....

Personally, I think you might just have a bad copy..

When I first got mine, it was wayyyyyy soft at all apertures, but after adjusting the focus on my d300, it got pretty sharp. On my d200 it's fine.

Here's a thread I made about mine on flickr
http://www.flickr.com/groups/afsnikkor35mm18/discuss/72157629507132322/?search=soft

 

[shadowlands]

I don't have mine anymore, but it was an awesome lens. I'll pick up another, one day.

 

[daggah]

The camera will always AF with the lens wide open. The aperture gets smaller only when you press the shutter.

The 'sweet spot' has nothing to do with auto-focus.

Sure it does. You'll never find it if your lens and camera combo has front or back-focusing issues, and you can't fix those on lower end DX DSLRs.

The camera will always AF with the lens wide open. The aperture gets smaller only when you press the shutter.

Or press a DOF Preview button.

You're not getting it. It has nothing to do with the camera autofocusing wide open or using a DOF preview button.

If your lens and camera body is front or back-focusing, you will not be able to accurately tell what the "sweet spot" is. The lens will seem like it's dreadfully soft until it's stopped down sufficiently that your test chart or whatever you're looking at is in the area that's in focus. An example fast prime's "sweet spot" may be f/2.8...but you won't know, because the depth of field may still be too shallow for you to see that.

 

[480sparky]

The camera will always AF with the lens wide open. The aperture gets smaller only when you press the shutter.

Sure it does. You'll never find it if your lens and camera combo has front or back-focusing issues, and you can't fix those on lower end DX DSLRs.

The camera will always AF with the lens wide open. The aperture gets smaller only when you press the shutter.

Or press a DOF Preview button.

You're not getting it. It has nothing to do with the camera autofocusing wide open or using a DOF preview button.

If your lens and camera body is front or back-focusing, you will not be able to accurately tell what the "sweet spot" is. The lens will seem like it's dreadfully soft until it's stopped down sufficiently that your test chart or whatever you're looking at is in the area that's in focus. An example fast prime's "sweet spot" may be f/2.8...but you won't know, because the depth of field may still be too shallow for you to see that.

Try again. And READ the posts.

What does the DOF Preview button have to do with 'the sweet spot'?


Think about it.

 

[daggah]

Try again. And READ the posts.

What does the DOF Preview button have to do with 'the sweet spot'?


Think about it.

Nothing. Which is why I didn't bring it up. Seriously? Your level of reading comprehension is incredibly poor.

You CANNOT accurately measure the sharpness of a lens if your sample shots aren't in focus.

Read THAT, and think about it.

 

[o hey tyler]

Nothing. Which is why I didn't bring it up. Seriously? Your level of reading comprehension is incredibly poor.

You CANNOT accurately measure the sharpness of a lens if your sample shots aren't in focus.

Read THAT, and think about it.

That's why you manually focus in live view and check for sharpness. Use AF to measure front or back focusing on a focus accuracy chart.

 

[daggah]

That's why you manually focus in live view and check for sharpness. Use AF to measure front or back focusing on a focus accuracy chart.

OK, so this nitpicky BS started when I pointed out how regrettable it was that you can't fine-tune AF on the entry-level Nikon bodies. You can use the manual-focus/live-view method for testing a lens, but it's not like you're going to be able to use this method for every-day shooting.

 

[Mach0]

OK, so this nitpicky BS started when I pointed out how regrettable it was that you can't fine-tune AF on the entry-level Nikon bodies. You can use the manual-focus/live-view method for testing a lens, but it's not like you're going to be able to use this method for every-day shooting.

Yes you can AF fine tune on the d7000 and I don't know what you would all a d600 but its a d7000 with a fx sensor.