It flies in the valley of Logs - Laprairie

This is a three image focus stack.

Interesting wood abstract.  I love dead trees, live trees, roots, etc.  Why the focus stacking? Greater depth of focus?

Steve: high "f" numbers like f22 give great depth of field but in the digital world it invokes digital diffraction which softens the image. So by going to an f8 or f5.6 the lens avoids digital diffraction but you have less depth of field. This is when I do the focus stacking.

Here is a good article on Digital diffraction where you can see the degradation of the image as you change the aperture.

 

A few years ago, someone rated one of my images quite low without comment. I was able to establish a professional discussion and that is how I learned about digital diffraction. Over the years I have encouraged the powers at photo.net to force people who rate low to make a comment but I suspect that is a costly venture.  I found someone who rated an image an automatic 3 if he thought you used HDR so for a while I stopped mentioning when I used HDR which can be a disadvantage to others in the community.

I will get down from my soap opera box

 

All the best

 

 

 

Thanks.

Tony,

i understand your reasoning for using focus stacking here, and the result is evident in the subtle but sharp features of the wood being visible everywhere in the image. In some cases, focus stacking can even be performed handheld without tripod, thanks to the power of Photoshop in aligning multiple images. I thought lens diffraction is an optical phenomenon that affects both film and digital images. The luminous landscape link that you provided is a great discussion on the subject. I remember many years back, I shot a waterfalls at f22, because I wanted long exposure in daylight and didn't have any ND filter. The printed enlargement looked horribly soft, even though properly focused and no tripod movement, the film was velvia.

Thanks for the explanation.  I Haven't tried focus stacking yet.  With the APS sensor maybe there is less of a problem, at least at wide angles, because wide angle with APS is such a short focal length.  I'm thinking of a shot I did years ago with my "new" D70 and the 18-70 lens.  I shot the dead tree at f20, at 18mm, and the print is nicely sharp with no evidence of diffraction.

 

You are absolutely correct that it affects both film and digital photography and the more accurate term is lens diffraction. At the levels displayed here at PN the difference is almost not discernible. Making 3 shots on the d810 at approximately 36 mp per image is a choice one carefully makes. I actually have a macro somewhere at Photonet where I shot 35 images to make one image . ...... pause I will see if I can find it .......  Can't find it.   

 

Focus stacking 35 images in Photoshop gave me trouble so I had to break it up into batches of 5. I was inspired to try that after I wrote to a photographer that had an incredible macro photo where everything was in focus. He told me he worked in a Lab and had access to equipment which facilitated him taking 100 images to get that one perfect shot.

 

Got to run and will be back again to respond to Steve.

 

Thanks. Your image looks great and as i mentioned, it is difficult for me to assess diffraction at this resolution.  I may be mistaken, but judging from the bottom left corner it looks a little softer than the rest and this maybe focus related or diffraction or my eyesight.  

 

All the best and thanks for the discussion.

Wonderfully sculptural shot. I especially like the way you've handled the light here but then again that seems to be your forte.

Tony, my shot with the D70 at f20 required no more sharpening in ps than at any other f stop.  I have 11x14 print that is sharp, and I am making a 16x20.  My 18-105 lens is definitely sharpest wide open, so lenses are different.  When I shot 4x5 I had a very old uncoated zeiss protar 90mm lens in a brass barrel.  It was optimal for sharpness at f22 and f32.  I have a couple shots in my film folder from this lens. Large format is different of course, than small format. 

Thank you for your kind words. The light colored wood caught my attention immediately walking in a very familiar area but not seeing this before.  A minor distraction was a wolfy looking dog with its tail in the down position walking around un-tethered and without an apparent owner. Before he even stepped into the water, mother duck with ducklings was making loud warning sounds.   

 

Thanks for responding. As the article in the link I provided indicates, testing each lens is important to see how diffraction affects it. I have only done this with my tamron 90mm and I try and avoid going past f11.  In the end, I believe that what is in the image is more important than getting it so crisp that it might cut me when I am shaving (*_*).

 

PS I try and close down a couple of stops from wide open to hopefully get the optimal performance from the lens I am using. Of course, I break that rule sometimes.

Interesting.  I was looking at raw images I shot in 2005-2006 with the 6mp D70 of trees and such at f22 with my 18-70 lens.  All are sharp with no real signs of image softness with normal sharpening.  I now have a different 18-70 so I can't make a direct comparison on the 24mp D7100, but images with my current 18-70 at f22 on the D7100 show very noticeable signs of diffraction.   I do think the larger pixel density of the newer cameras is more sensitive to lens properties, but, I am not an expert in optics.

I still have my D70 and the nikkor 18-70mm kit lens.  Time permitting, I must experiment.

I really must do something with lens that I don't use much these days e.g. sigma 10-20mm since I acquired the nikkor 20 mm 1.8.