Lobster Rolls, Lens Diffraction, And Getting The Real Scoop
Posted: Sun Sep 12, 2010 2:46 pm
Having spent a good deal of time on the New Enland Atlantic coast in recent years (Maine in particular) - one invariably comes face to face with the age old question..."who makes the best Lobster Roll?" Well I value my time and lobster rolls - so I like to get as much real "boots on the ground" information as I can. I'm not just going to take on face value..."there's only one really good place - and that's in Wiscasset" - I'm going to look into it as much as I can before hand...and get the real scoop.
To wit, recently I was in a wonderful day long seminar with the photographer Art Wolfe - the well known landscape photographer and host of a public TV program called "Travels To The Edge" which follows him on some of his photography excursions. We got to see many many wonderful pictures, and get the background...all a truly great experience. Then later, Art stopped to talk about his gear and technique a little bit...and then talked about aperture use in landscape photography. He said that when he has finally sized up the image, and got the tripod situated - he always stops down to f22 or what ever the maximum is on the lens he is using. Well, as soon as I heard him say that a big octagonal shape appeared in my minds eye...colored bright red...with big white letters spelling out... STOP! You know it sounded just like someone telling me..."well the best lobster roll on the East Coast is...". I paused for a moment an thought...is this the absolute best thinking?...always?...how in the world is he accounting for lens diffraction? Lens diffraction from higher f stops can potentially ruin a landscape image by adding blurriness - even though at higher f stops depth of field increases. What critical information Art did not mention was at some point on some lenses and for some images - the lens diffraction blur can totally offset any increase in depth of field - and that is a really big deal. Some lenses may be more prone to it, and if shooting an image with a lot of bright reflectance - back light, snow scenes, etc. - then you're really going to potentially get a lot more of it. I personally experiment with my lenses to see how much of it occurs and have some idea what my best options are, and of course when shooting something important I will shoot stops from f11 all the way to f18 ust to have options to compare later. Note that my Zuiko 12-60 mm has a sweet spot somewhere between f14 and f16 - I never shoot at f22 with that lens. I'll never forget shooting a beautiful Greek Revival white church in freshly fallen snow with magical morning sun light - right after I first got that lens...all the best compositions I shot at f22. I looked at them later...all unusuable. The only shots from that morning that really looked good were shot at f9. The magical moment and subject gone forever...lesson learned.
Other important ancillary considerations for those of us who love shooting foliage is leaves and windspeed - these have to be considered carefully as well, before using the highest f-stops (note that if you use a camera that shoots usable images at ISO 1600 and above you can get some faster shutter speeds - so you may have a little less to worry about here). If you decide you want to shoot a scene with a lot of leaves and the wind is blowing 10 mph or so - one needs to consider how fast a shutter speed is needed to stop that action. If you follow the "stop down to f22" you may (of course adding into the equation the amount of ambient light of course) not have a fast enough shutter speed to stop the action, THEN combined with lens diffraction...the image will become noticeably blurred in its finest details. I have had very good landscape images produced using f7 ( I don't do this as a rule or often) or so - just get a fast enough shutter speed to stop windblown foliage in the foreground. This extreme sharpness in the foreground can trick the eye into thinking an image has front to back sharpeness to some degree even with a shallower depth of field. When I studied doc. camera with Bestor Cram at the Maine Media Workshops several years ago - if an image was not in focus or enough in focus - it was eliminated.There wasn't any further discussion ...none...nada.
As an aside, I recently ran across the work of a professional photographer (way above my pay grade) who has had many books published. Almost all of the leaves or foliage in any of his outdoor shots is slightly blurry, and has ugly artifacts of lens reflectance. He is of the "stop down to f22 no matter what" school - and partly because of his camera and lenses, and partly because he's never really tested to see.... he never gets truly satisfactory focus results sad to say. I wish I saw less of this, but c'est la vie.
Finally, while I have my favorite Lobster Rolls (and have eaten hundreds and hundreds in my search for the best) - that of course is all still somewhat subjective. I've included, however, a link (I happen to like Cambridge tutorials but you can Google a bit for more info.) dealing with factual provable effects of lens diffracton which be of some help to us all as we prepare to make our way this October to those magical places full of the most wonderful fall foliage.
http://www.cambridgeincolour.com/tutori ... graphy.htm
To wit, recently I was in a wonderful day long seminar with the photographer Art Wolfe - the well known landscape photographer and host of a public TV program called "Travels To The Edge" which follows him on some of his photography excursions. We got to see many many wonderful pictures, and get the background...all a truly great experience. Then later, Art stopped to talk about his gear and technique a little bit...and then talked about aperture use in landscape photography. He said that when he has finally sized up the image, and got the tripod situated - he always stops down to f22 or what ever the maximum is on the lens he is using. Well, as soon as I heard him say that a big octagonal shape appeared in my minds eye...colored bright red...with big white letters spelling out... STOP! You know it sounded just like someone telling me..."well the best lobster roll on the East Coast is...". I paused for a moment an thought...is this the absolute best thinking?...always?...how in the world is he accounting for lens diffraction? Lens diffraction from higher f stops can potentially ruin a landscape image by adding blurriness - even though at higher f stops depth of field increases. What critical information Art did not mention was at some point on some lenses and for some images - the lens diffraction blur can totally offset any increase in depth of field - and that is a really big deal. Some lenses may be more prone to it, and if shooting an image with a lot of bright reflectance - back light, snow scenes, etc. - then you're really going to potentially get a lot more of it. I personally experiment with my lenses to see how much of it occurs and have some idea what my best options are, and of course when shooting something important I will shoot stops from f11 all the way to f18 ust to have options to compare later. Note that my Zuiko 12-60 mm has a sweet spot somewhere between f14 and f16 - I never shoot at f22 with that lens. I'll never forget shooting a beautiful Greek Revival white church in freshly fallen snow with magical morning sun light - right after I first got that lens...all the best compositions I shot at f22. I looked at them later...all unusuable. The only shots from that morning that really looked good were shot at f9. The magical moment and subject gone forever...lesson learned.
Other important ancillary considerations for those of us who love shooting foliage is leaves and windspeed - these have to be considered carefully as well, before using the highest f-stops (note that if you use a camera that shoots usable images at ISO 1600 and above you can get some faster shutter speeds - so you may have a little less to worry about here). If you decide you want to shoot a scene with a lot of leaves and the wind is blowing 10 mph or so - one needs to consider how fast a shutter speed is needed to stop that action. If you follow the "stop down to f22" you may (of course adding into the equation the amount of ambient light of course) not have a fast enough shutter speed to stop the action, THEN combined with lens diffraction...the image will become noticeably blurred in its finest details. I have had very good landscape images produced using f7 ( I don't do this as a rule or often) or so - just get a fast enough shutter speed to stop windblown foliage in the foreground. This extreme sharpness in the foreground can trick the eye into thinking an image has front to back sharpeness to some degree even with a shallower depth of field. When I studied doc. camera with Bestor Cram at the Maine Media Workshops several years ago - if an image was not in focus or enough in focus - it was eliminated.There wasn't any further discussion ...none...nada.
As an aside, I recently ran across the work of a professional photographer (way above my pay grade) who has had many books published. Almost all of the leaves or foliage in any of his outdoor shots is slightly blurry, and has ugly artifacts of lens reflectance. He is of the "stop down to f22 no matter what" school - and partly because of his camera and lenses, and partly because he's never really tested to see.... he never gets truly satisfactory focus results sad to say. I wish I saw less of this, but c'est la vie.
Finally, while I have my favorite Lobster Rolls (and have eaten hundreds and hundreds in my search for the best) - that of course is all still somewhat subjective. I've included, however, a link (I happen to like Cambridge tutorials but you can Google a bit for more info.) dealing with factual provable effects of lens diffracton which be of some help to us all as we prepare to make our way this October to those magical places full of the most wonderful fall foliage.
http://www.cambridgeincolour.com/tutori ... graphy.htm