6 replies to this topic

[Kevgarlic]

I have been having GREAT success with my Nikon D810.  However, is it just me, or a setting that I have not mastered, because sometimes my photos are

not as sharp as I think they should be.  Even at F-10.  I have two samples attached.  Both taken in autofocus and basically the same composition.

I can see why the F/4 will have a smaller depth of field, BUT, looking at the F/10 the picture should be tack sharp from edge to edge...thoughts?

What am I not doing right?

 

Thanks.

Kevin/Illinois

 

Picture #1  "ShelfMushroomsJPGMossyTreeZoomedInSmallerSize"

Details:  F/10

              1/60

              Focal Length  44mm

              Metering Mode  PATTERN (or MATRIX if opened in photoshop elements 10)

 

Picture  #2  "ShelfMushroomsJPG..OnMossyTree."

Details:  F/4

              1/400

              Focal Length  44mm

              Metering Mode  PATTERN  (or MATRIX if opened in photoshop elements 10)

Attached Thumbnails

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[ScottinPollock]

First, I don't recall any lens I have used that is at its sharpest at F10. Usually they are at their best at 1.5 to 2.5 stops down from wide open. And even at their best, most lenses are not tack sharp edge to edge, especially on full frame sensors.

 

Second is that if you're using the viewfinder, you're using an off sensor phase detect auto focus system. This is not as accurate as contrast detect auto focus systems. There also can be some mis-calibration issues between some bodies and some lenses with this kind of system.

 

To really be able to verify the sharpness of your setup, turn VR off (if equipped), mount on a solid tripod, and focus on a well lit scene with reasonable contrast using live view focusing. If your camera can lock the mirror up when exposing in Live View (dunno if the D810 can do this) then by all means set it that way.

 

It will then be easy to see which aperture for each lens is at its sharpest, and overall what can be achieved with your hardware (or whether it needs calibration for phase detect focusing).

[Kevgarlic]

Thanks Scott.

 

This helps TREMENDOUSLY.  I'll do that set-up test and confirm..since my most wide open F-Stop is 4.5 I'll do what you suggest and start my test around

F-6  or F-7.

 

This explains why in the past when I had been experimenting in the field and I would really shut it down to a crazy small aperture   --  like F-14 or even F-22   --

 

I would not see any sharpness improvement.  Yeah, I also did not know that Full Frame sensors especially did not have edge to edge sharpness.

 

Appreciate it.

Kevin/Illinois

[ScottinPollock]

I had been experimenting in the field and I would really shut it down to a crazy small aperture like F-14 or even F-22

With some lenses, diffraction starts to set in as soon as F11.

[Fstoppers Original] What Is Lens Diffraction And When Does Diffraction Happen? | Fstoppers

I also did not know that Full Frame sensors especially did not have edge to edge sharpness.

It is not the sensor per se, but the fact that lenses have to project their full image circle on the larger plane, which usually contains some amount of softness and light falloff around the perimeter. Since a crop sensor's plane is only about two thirds the area of FF, you don't see the edges.

[TBonz]

While Scott has given you good info, you do not indicate which lens...a high end body like the D810 can show flaws in "lesser" lenses.  You list the focal length as 44 so I am assuming it is some zoom...

[dem]

I have two samples attached.  Both taken in autofocus and basically the same composition.

They do not have the same composition. They are two completely different images.

 

The bottom part of each image seems to be in sharp focus. I don't think there is any camera shake in either case.

 

What you see is a shallow depth of field typical for close up images. The tighter the framing, the more blur you get around the areas of sharp focus. F/10 or even F/22 can often be not enough to render the whole image sharp. That's why people use focus stacking when photographing flowers, mushrooms and such. 

[Kevgarlic]

TBonz.  My lens is the kit lense which came with my D810  --  it is a AF-S Nikkor 24-120  lens.  So, yes, it is a Zoom, not a Prime lens.

dem.

Thanks for the information...I have touched the surface on "Focus stacking" perhaps I need to try that technique.

Kevin