
Acceptable sharpness with wide-angles
#1
Posted 03 November 2006 - 05:33 AM
I'm interested to hear other views though (and no Canon FF vs. Nikon APS format please, as the formats have differences which are often not equatable) and especially whether this was an issue on fim or whether it has become an issue due to "pixel peeping".
Paul Kay,Canon EOS5DII SEACAM c/w S45, 8-15, 24L,35L, 60/2.8 (+Ext12II) & 100/2.8 Macros - Sony A7II SEACAM 28/2 & 50/2.8 Macro - UK/Ireland Seacam Sales -see marinewildlife
#2
Posted 03 November 2006 - 06:27 AM
I buy my own photographic kit. Diving equipment manufacturers and diving services suppliers get even-handed treatment from me whether they choose to advertise in the publications I write for or not. All the equipment I get on loan is returned as soon as it is finished with. Did you know you can now get Diver Mag as an iPad/Android app?
#3
Posted 03 November 2006 - 06:59 AM
I would be interested to hear whether people felt that the Nikonos rectilinear water contact primes had better corner sharpness than dome ports - with their UW optics. The 15mm and 20-35mm AF in particular were always praised for their sharpness. But like Paul says people were such measurebators in those days.
And coincidently, I am giving an hour long talk at the Visions conference on the subject of shooting with fisheyes this weekend.

Alex
Alexander Mustard - www.amustard.com - www.magic-filters.com
Nikon D5 (Subal housing). Nikon D7200 (Subal housing). Olympus EPL-5 (Nauticam housing).
#4
Posted 03 November 2006 - 07:30 AM
#5
Posted 03 November 2006 - 08:21 AM
Just a point. I think you will find that the Nikonos 15 rectilinear lens is behind its own built-in dome port. The front element is only a lens when in contact with water! Put simply, it is precisely built. And very good it is too. That is the quality I sought to emulate when I went to a housed camera.
I buy my own photographic kit. Diving equipment manufacturers and diving services suppliers get even-handed treatment from me whether they choose to advertise in the publications I write for or not. All the equipment I get on loan is returned as soon as it is finished with. Did you know you can now get Diver Mag as an iPad/Android app?
#6
Posted 03 November 2006 - 10:49 AM
Absolutely. There is no doubt in my mind the Nik 15mm was the crispest throughout the frame, and current rectilinears behind a dome port only wish they were as tack.<snip>I would be interested to hear whether people felt that the Nikonos rectilinear water contact primes had better corner sharpness than dome ports - with their UW optics. The 15mm and 20-35mm AF in particular were always praised for their sharpness. <snip>
I will confess I occasionally (wistfully) wish for a re-run of the Aquatica megadome. 14" IIRC.
And to address your question, Paul, for me, accecptable corner sharpness is just as tack in the corners as the center. Which I don't often get.
I'd rather have the sharpness to Photoshop out if I want to, than wish for it when I need it.
All the best, James
#7
Posted 03 November 2006 - 03:40 PM
Many wide lens/ port / full frame sensor combos need a + diopter up front, which to my eye has always reduced image sharpness all over, but especially on the edges (even the best diopters).
Even on land when I use my EF16-35mm2.8L to do anything I want sharp throughout, I have to shoot at f11.5 or 16. f22 it goes soft right across - at f11 and wider the edges are really bad...put the diopter on and it is worse.
With dig there is also the issue of light refracting through the flat glass filter on front of the sensor that may make more of a difference toward the edges. Also note that Leica have started putting a lens on front sensors at edge of frame to help wide angle resolution. http://www.dpreview....ticles/leicam8/
I am a 20+ year Canon film / now full frame dig user on land, but my recent change to digital U/W saw me choose small sensor camera (Nikon d200)/Seacam Superdome combo specifically to provide a solution that meant no diopter, plus the bonus of increased depth of field at any given angle of view/aperture combination the shorter focal length provides.
All in the search for better/even sharpness across the frame. I felt a higher pixel count in a full frame system would always be compomised by the diopter in front of the lens.
And yes, as mentioned in earlier posts, everyone AD looks closer than BD.
Great thread!
Edited by photovan, 03 November 2006 - 03:43 PM.
Darren Jew | Australia | darrenjew.com | fotofrenzy.com.au
Canon EOS1Dx | EOSM | Nauticam | Inon Z240
#8
Posted 04 November 2006 - 10:53 AM
BUT (and not wanting to start on different camera systems as both the main players produce 'smaller' format cameras, although currently fast wides are only available on one), I have shot, and intend to shoot in the future, at very wide apertures underwater! Admittedly working this way suits only a few subjects, but then if everything was shot in the same way wouldn't photography be boring. At the moment using wide apertures is tricky because any corner subject matter has to be very carefully considered (but they can be used to reasonable effect) - if it isn't then really unpleasant corners are a result. And using FF as opposed to APS types effectively gives shallower DoF.
I'm also intrigued to realise that we underwater photographers are prepared to accept image quality which would quite simply not be acceptable to topside photographers. Realising this might make more of us pursue potential remedies - however potentially expensive these may seem.
Alex might like to consider the potential of Magic Filters wide-angles and fast apertures - substantially enhanced creativity.
Comments?
Paul Kay,Canon EOS5DII SEACAM c/w S45, 8-15, 24L,35L, 60/2.8 (+Ext12II) & 100/2.8 Macros - Sony A7II SEACAM 28/2 & 50/2.8 Macro - UK/Ireland Seacam Sales -see marinewildlife
#9
Posted 04 November 2006 - 01:04 PM
It's a nice effect when pulled off, I suppose you'll be thinking the 24mm and 35mm f1.4s to get those out of focus areas blurry enough?
Maybe one of the new 'blad hd3s housed with the 95degree/28mm - even though its only f4, it might be good for the job.
Darren Jew | Australia | darrenjew.com | fotofrenzy.com.au
Canon EOS1Dx | EOSM | Nauticam | Inon Z240
#10
Posted 04 November 2006 - 02:12 PM

Edited by anthp, 05 November 2006 - 03:32 PM.
anthonyplummer.com
"It's much better down there... It's a better place..." Enzo, Le Grand Bleu.
#11
Posted 04 November 2006 - 02:49 PM
I buy my own photographic kit. Diving equipment manufacturers and diving services suppliers get even-handed treatment from me whether they choose to advertise in the publications I write for or not. All the equipment I get on loan is returned as soon as it is finished with. Did you know you can now get Diver Mag as an iPad/Android app?
#12
Posted 04 November 2006 - 02:58 PM
Darren Jew | Australia | darrenjew.com | fotofrenzy.com.au
Canon EOS1Dx | EOSM | Nauticam | Inon Z240
#13
Posted 05 November 2006 - 06:09 AM
here's an illustration of what can be achieved at the moment. Shot with a 24/1.4 at 1.4 on the 'Rainbow Warrior' the interesting thing about the shot is that the areas which are sharp represent ones which are certainly not planar. Currently this technique suits itself to very limited subject matter and images. Whether you like it or not is another question.

Paul Kay,Canon EOS5DII SEACAM c/w S45, 8-15, 24L,35L, 60/2.8 (+Ext12II) & 100/2.8 Macros - Sony A7II SEACAM 28/2 & 50/2.8 Macro - UK/Ireland Seacam Sales -see marinewildlife
#14
Posted 05 November 2006 - 07:14 AM
Sorted out how to get a Lens Baby working UW yet?
darren
Darren Jew | Australia | darrenjew.com | fotofrenzy.com.au
Canon EOS1Dx | EOSM | Nauticam | Inon Z240
#15
Posted 06 November 2006 - 12:43 AM

Paul Kay,Canon EOS5DII SEACAM c/w S45, 8-15, 24L,35L, 60/2.8 (+Ext12II) & 100/2.8 Macros - Sony A7II SEACAM 28/2 & 50/2.8 Macro - UK/Ireland Seacam Sales -see marinewildlife
#16
Posted 06 November 2006 - 02:38 AM
anthonyplummer.com
"It's much better down there... It's a better place..." Enzo, Le Grand Bleu.
#17
Posted 06 November 2006 - 06:43 AM

Paul Kay,Canon EOS5DII SEACAM c/w S45, 8-15, 24L,35L, 60/2.8 (+Ext12II) & 100/2.8 Macros - Sony A7II SEACAM 28/2 & 50/2.8 Macro - UK/Ireland Seacam Sales -see marinewildlife
#18
Posted 06 November 2006 - 06:53 AM
#19
Posted 09 November 2006 - 03:16 AM
... what contributes most to sharpness in u/w images? Optics or turbidity? A poorly matched combination of dome and lens is frustrating, but you can compose around it, in the same way as you can compose around the distortions of a fisheye lens. If the Nik 15mm was so brilliant, then why did everyone bother to struggle with domes and SLRs? Was it the ability to compose through the lens?
The perception of sharpness depends as much upon the contrast as the resolution of an image: this is easily seen in a darkroom, and, now, in Photoshop. I thinnk that this is why monochrome wreck images are so impressive, and why Paul's diver is better than his fish, above. It is difficult to light the edges of a w/a frame, and this exaggerates the problem.
Besides, how important is sharpness? I went to Visions in London last weekend, and was intrigued by Amos Nachoum's big-animal photography. All of his terrestrial images where as sharp as possible, but the u/w ones often soft, but so impressive - because of the subjects in front of the lens. The technical aspects certainly contribute to the image, but they aren't the heart of the matter. Sharpness is a tool, like colour, and, like colour isn't always necessary or (perhaps) even appropriate.
Tim
#20
Posted 09 November 2006 - 04:12 AM
...If the Nik 15mm was so brilliant, then why did everyone bother to struggle with domes and SLRs? Was it the ability to compose through the lens?...
I changed to a housed system from Nikonos V (never got to try RS) so that the process of u/w photography was more like topside shooting; more "photographic" I suppose. Nikonos was always so "point-and-shoot" in my opinion. So the main issue for me was being in control the camera, not being at the mercy of the camera. Having said that, my most popular u/w pic was shot with the Nikonos V/15mm combo....
Besides, how important is sharpness? I went to Visions in London last weekend, and was intrigued by Amos Nachoum's big-animal photography. All of his terrestrial images where as sharp as possible, but the u/w ones often soft, but so impressive - because of the subjects in front of the lens. The technical aspects certainly contribute to the image, but they aren't the heart of the matter. Sharpness is a tool, like colour, and, like colour isn't always necessary or (perhaps) even appropriate.
I agree that sharpness, or lack of it, is one just one of the many tools available, and sharpness is sometimes overrated. But when choosing how to interpret a subject, I would prefer to be making the sharpness/lack of sharpness decisions for myself rather than being at the mercy of equipment design. If I want it sharp, I prefer it to be sharp (well as sharp as possible anyway).
Colour and contrast (and even exposure to some degree) even blur might be post processing issues now-a-days, but sharpness is still in the capture domain.
Darren Jew | Australia | darrenjew.com | fotofrenzy.com.au
Canon EOS1Dx | EOSM | Nauticam | Inon Z240