Lacking sharpness on 100% crop

[neevo]

I have a macro question that I am hoping you can help me with. Setup at the moment consists of:

D70s
Nikon 70-210 or 50mm
Kenko Extension Tubes
Speedlight SB-600

I am using manual focus for my shots and have been experimenting with my newly purchased speedlight to up the shutter speed. I can get reliable shots with speeds of around 1/250 to 1/400 however when I check at 100% the shots lack a huge amount of sharpness.

This isn't consigned to my macro shots only either, when I do 100% crops on my regular shots I get similar sharpness. I am using custom settings on the camera (no sharpening, +2 tone comp, IIIa Colour, + saturation, -3 hue).

Is this an issue with my technique overall, an artifact of the camera or am I just expecting too much from this setup. I would assume the latter is maybe not the answer as I do get the odd shot that is tack sharp but this is the exception rather than the rule.

Here are some images to see what I am talking about:

Shutter: 1/250
Aperture: f7
Mode: Manual
Flash: Remote fired SB-600
Focal Length: 70mm
Extension: 72mm



100% crop



Thanks in advance.

[Major_Small]

That's something you'll find with almost all cameras. Top-of-the-line glass will help out, but it's really a limitation of the cameras. Even film has a similar limitation. It's just that it can only resolve to a certain point.

This is part of the reason almost all images can benefit from some PP. Usually an unsharp mask fixes this up nicely. Another thing that helps is scaling down the image. You won't be able to print it as big, but sometimes you need to lose a little size for quality.

[neevo]

So upgrading to a D200 would help with this issue?

[neevo]

I just tried experimenting with some of the sharpening settings on the camera and that seems to have made quite a bit of difference.

The tests were in the front room and not "in the field" but hopefully that should have some impact.

[elrebrin]

Try a larger aperture (smaller f-number). This should reduce the amount of diffraction caused by the iris and help give you a sharper image. Of course, this comes at the cost of depth of field.

Cheers,

Chris

[neevo]

I am not sure if diffraction is going to be an issue at f7. This lens stops down to f32 and I am pretty confident that the sweet spot is up to f16 before diffraction kicks in.

Here is an image from f13 with the same setup (minus the speedlight) so I know the lens can produce acceptable images:

[jdepould]

Stop pixel peeping!

In all seriousness, if the image looks good at a normal display size, it'll print fine, and that's really all that matters. You don't view images at 100% so don't worry about it.

[neevo]

Originally Posted by jdepould

Stop pixel peeping!

In all seriousness, if the image looks good at a normal display size, it'll print fine, and that's really all that matters. You don't view images at 100% so don't worry about it.

I definately hear you, but I love sharpness and if there is some part of my technique that I can improve then I am eager to do that.

[inkista]

It's a rare lens that can hold up to the 100% crop thing.
It looks like your technique is pretty good: high enough shutter speed, small enough aperture.

f/8 tends to be the sharpness sweet spot, you lose sharpness to diffraction with a crop body starting at f/16, so working between those two apertures are going to help you the most.

With macro photography, using a tripod and a remote/timer to eliminate handheld camera shake are probably also going to gain you a little, if the blur is coming from motion blur. You may also want to consider focus bracketing and/or focus stacking, and using mirror lock-up. Macro photography tends to magnify any movement.