Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
09-16-2016, 03:26 AM   #31
Veteran Member




Join Date: Jun 2008
Location: Flyover America
Posts: 4,475
Without comment:
Sigma 105mm macro+K20, f/32, f/32, f/22


Last edited by wildman; 09-19-2016 at 04:57 PM.
09-16-2016, 06:55 AM   #32
Pentaxian
normhead's Avatar

Join Date: Jun 2007
Location: Near Algonquin Park
Photos: Gallery | Albums
Posts: 33,575
[quote=MikeD;3773279]Norm
I share your feelings completely and agree with every point you made. Thank you for one of (if not the best) posts I have ever read on PF. I am curious about your sequences why you skip F8 in your expanded sequence and how you determine which you use.

Mike

---------- Post added 09-16-2016 at 12:52 AM ----------





I don't always skip ƒ8 , just stated that way for clarity. I Like to miss a stop where possible just in terms of simplification. I try and keep it to five exposures and that mens an educated guess and missing some stops. But, los of time, there has been has appeared that a stop I skipped was the one I would have liked best.

QuoteOriginally posted by MikeD Quote
Norm
another question - your feelings on diffraction at f32 for macro work. Do you feel diffraction is a result of small aperture
and distance where being very close to the subject minimizes or eliminates diffraction.
I've wondered about that issue, being close helping eliminate diffraction, but i've never tested that. Believe it or not I'm actually quite reluctant to comment on technical issues with which I haven't done the work necessary to have a bit of basis to my opinion. There are times where you just have to say "I know nutink". But I have thought about it, so there might be something to it.
09-16-2016, 06:55 AM   #33
Brooke Meyer
Guest




QuoteOriginally posted by wildman Quote
Without comment:
Sigma 105mm macro+K20, f/32, f/32, f/22
Also on K-20 at f32, with a Tamron 1.4 TC and Tamron 28-75 and softer, morning overcast. Uncropped. Kept thinking, Georgia O'Keefe on the first.

Last edited by Brooke Meyer; 12-10-2016 at 12:15 AM.
09-16-2016, 07:19 AM   #34
Pentaxian
photoptimist's Avatar

Join Date: Jul 2016
Photos: Albums
Posts: 3,677
QuoteOriginally posted by MikeD Quote
another question - your feelings on diffraction at f32 for macro work. Do you feel diffraction is a result of small aperture
and distance where being very close to the subject minimizes or eliminates diffraction.
From an optical physics point of view, macro makes diffraction much worse because diffraction is an angular spreading of the light and the lens is moving further from the sensor creating more distance for diffractive spreading. To a first approximation, f/16 in a 1:1 magnification macro image has as much diffraction blur as f/32 would for a landscape image.

But.. and it's a big but.... From a perceptual point of view (and that's what really matters in most photography), it's the opposite. In macro, the zone of focus is so thin and the degree of blurring in foreground and background is so broad that a narrower aperture creates huge improvements in the perceived image sharpness.

That is, the image looks better even if it is worse.

09-16-2016, 07:21 AM   #35
Veteran Member




Join Date: Jun 2008
Location: Flyover America
Posts: 4,475
QuoteOriginally posted by Brooke Meyer Quote
Georgia O'Keefe
The irony is that Georgia, once she understood the technical aspects of diffraction in her camera, might have said...

...wonderful!, now I have another creative control I can apply to my images. You photographer's can't image how difficult it would be to mimic diffraction in painting.

Last edited by wildman; 09-16-2016 at 07:29 AM.
09-16-2016, 07:27 AM   #36
Pentaxian
normhead's Avatar

Join Date: Jun 2007
Location: Near Algonquin Park
Photos: Gallery | Albums
Posts: 33,575
QuoteOriginally posted by photoptimist Quote
That is, the image looks better even if it is worse.
And that's the thing for photographers, we don't care if it's technically better, as long as it looks better. The other thing there that close ups have in their favour is the better resolution the closer you get thing. reduced involvement of atmospheric distortions etc. With nights going down to near freezing and day time temperatures in the 70s right now, I can go over to Opeongo lake an take and image of the 1 km away ridges at ƒ8 you'd swear were taken at ƒ45. The various heat pockets, different levels of humidity etc. pretty much makes even the sharpest lens look like mush in some circumstances. I would easily shoot an ƒ22 macro from the same location.
09-16-2016, 09:20 AM   #37
Veteran Member




Join Date: Jun 2008
Location: Flyover America
Posts: 4,475
QuoteOriginally posted by photoptimist Quote
the image looks better even if it is worse.
I would only refine it a bit...

...the image looks better even if, in the narrow technical sense, it is "worse".
09-16-2016, 09:35 AM   #38
Veteran Member
emalvick's Avatar

Join Date: Feb 2008
Location: Davis, CA
Photos: Gallery
Posts: 1,623
I have to admit that while I understand the physics of what happens with diffraction, I really pay very little detailed attention to it in shooting. I tend to shoot from my experience with diffraction than any hard and fast rule.

My own finding has been that where diffraction occurs has been highly dependent on the specific lens. Does that make sense? It could be coincidental, too. I never thought much of how focal length mattered because I think my observation went more with the quality of the lens rather than any attention to focal lengths. Some lenses, I'd notice diffraction kicking in at f/11 and others I wouldn't notice until I was at an aperture smaller than f/16. I've since replaced most the lens that I had diffraction issues with at larger apertures, not specifically because of diffraction. Those lenses were either slower or lacked overall sharpness, which I suppose would relate.

These days, I am conscience of what I shoot at with regards to aperture. I find myself rarely shooting at smaller apertures than f/13 unless I have a specific need (depth of field). But, I have not specifically had issues when I do shoot to f/22, which I do occasionally do.

I guess I think of shooting f/22 more in line of how I concern myself with noise. I'm willing to shoot above ISO 6400 if needed and have prints at ISO 12800 that are completely acceptable. Diffraction on the screen does not always translate to a print. Once I'm printing at 300 dpi, the flaws of something like diffraction and general softness are not as obvious as on a computer screen. I'm not saying they aren't there, but it takes more effort to notice.

09-16-2016, 11:11 AM   #39
Site Supporter
Site Supporter
Pioneer's Avatar

Join Date: Aug 2009
Location: Elko, Nevada
Photos: Gallery | Albums
Posts: 1,289
Wildman and Brooke Meyer, those photographs are simply superb.

I really could care less about the aperture used as it is all about the visual experience. I could sit here and look at those hanging on my wall for hours.

Thank you
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
36x24, aperture, aps-c, book, camera, diffraction, dof, effects, f/16, focus, image, images, photography, product, razor, sequence, sharpness, step
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
I Must be stupid ! Bought a K-3II instead of what I wanted.....was owed $$$ Dlanor Sekao Pentax DSLR Discussion 35 04-26-2016 12:00 PM
Why didn't I know this??? Zephos Photographic Technique 20 03-02-2016 12:08 PM
Can't Believe I Didn't Know This (Feeling Stupid) OrangeKx General Photography 31 12-22-2014 11:15 AM
I didn't know Samsung cameras used the K mount Michael Piziak Pentax DSLR Discussion 17 06-08-2014 09:35 PM
J.K. Rowling: ĎI didnít build thisí on my own jeffkrol General Talk 4 10-01-2012 02:22 PM



All times are GMT -7. The time now is 06:54 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top