Can anyone help? Hyper focal distance question

[Scottie68]

I wonder if anyone can help as this has been driving mad for a while now.

Below, i have taken 2 identical photo's. One is at F11 and the other is at F22. Both have been set to the hyper focal distance for 32mm. The pictures shown have only been saved as jpeg and were taken as raw, so now sharpening at all has been applied to the either photo's. Even when i do sharpen F22 photo's, they are far from pin sharp front to back as they should be. The F11 photo is much better. So can anyone tell me why the F22 photo is not sharp, even when i try to sharpen? Any help with this would be gratefully appreciated

Taken with Nikon D700, Nikon 24-70mm using a lee big stopper

Do you also think i need my sensor cleaning? The dust particles are getting quite bad on the F22 photo

F22

F22 by surfinscottie, on Flickr

F11

F11 by surfinscottie, on Flickr

Edited ... original photos too large ... sorry folks :bonk:

 

[dinners]

That killed my PC for ten minutes.

Perhaps F11 is just closer to the optimum than f22 for the lens.

Your dust will also appear worse with narrower apertures.

 

[CT]

LOL. I think these may be just a smidge over forum size limits.

At f22, diffraction tends to become an issue. The light being squeezed through that tiny aperture hole hits the aperture blades and gets bounced and scattered around within the lens spoiling the definition. F8 or f11 tends to be the sweet spot before diffraction sets in.

Even then diffraction isn't really an issue at normal print sizes. Why have you shown these images at this size? If it's because you intend to print at this size, then viewing distance becomes a part of judging sharpness. If you stick a huge print on the wall and get your nose close to look at it you're going to find fault - step back to normal viewing distance and it will look fine.

And yes - you have a few dust bunnies at f22 which really shows them up - but far from bad. Personally I'd just touch them out in editing.

 

[Scottie68]

Thank you for the replies. Sorry the images are so large, didn't mean to put them on at this size. I will put smaller images on in the morning as I'm now on my iPhone. Sorry once again.

I understand that most sweet spots are F8-F11, but if I am taking landscape shots, does that mean I can use F11 for example to get better quality shots? I was always lead to believe that most landscape shots were taken at F16-F22?

 

[CT]

I think you can see for yourself that your f/11 shot is much sharper. I don't think you need to look much further for your answer.

That shot is pretty good for an unsharpened image at that size. I'm not going to sharpen it and post it at that size though, they'd have to put two blokes on overtime at the power station!

 

[HoppyUK]

Problem is diffraction, as stated above.

HFD with a 32mm lens on full frame D700 is 14ft at f/8, which will give you depth of field from 7ft to infinity www.dofmaster.com

Your lens will be best at f/8 and sharpness should hold up very well to f/11. I try to avoid f/16 and never use f/22 unless there's no other option. If you get the HFD right there's rarely any need to go to f/22. How far away were those foreground rocks?

Remember that if maximum sharpness is the plan, then using HFD technique by definition (haha!) puts infinity right at the limit of acceptable sharpness. In that situation, if the DoF tables say f/8 is okay, then I would go to f/11 - the tiny loss of sharpness through increased diffraction would be more than off-set by the greater depth of field pulling the far distance further within the DoF zone.

 

[Uneducated_Rick]

f22 also has significantly longer shutter speed

the trees, the reflection of the trees in the water, and clouds are fuzzier because they are moving with the wind

the foreground rocks and background hill don't show anywhere near the same degradation as the 'movable' objects on the small images I can see - unfortunately the full sized ones are restricted on flickr so I can't look at the full size shots


also if you have two different apertures surely the hyperfocal distances will be different?

 

[Scottie68]

Problem is diffraction, as stated above.

How far away were those foreground rocks?

They were aprox 15ft away

f22 also has significantly longer shutter speed
also if you have two different apertures surely the hyperfocal distances will be different?

Yes they were both different. I used the DOF chart to set the HFD

Images have been resized and thank you all for your answers. Looks like i will be keeping away from F22 unless critical

 

[Scottie68]

One more question if I may ....

When setting the hyperfocal distance using the DOF chart, is it the overall focal length of the lens (ie 16-35mm) 35mm, or the actual length I have set my lens at, say 24mm?

 

[HoppyUK]

One more question if I may ....

When setting the hyperfocal distance using the DOF chart, is it the overall focal length of the lens (ie 16-35mm) 35mm, or the actual length I have set my lens at, say 24mm?

The actual focal length set.