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StephenFrink

Member Since 11 Dec 2002
Offline Last Active Jan 18 2015 05:10 AM
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Posts I've Made

In Topic: Full Frame SLR wide angle corrector port tests

29 December 2014 - 06:08 PM

If you look at the very small type on the lower left of the res chart it reveals the optical corrector being significantly sharper. This is not corner noodling, as this would be an important part of most any composition. Looks like you are on to something, Alex. Great initiative and a promising direction.

In Topic: Full Frame SLR wide angle corrector port tests

25 December 2014 - 07:01 PM

Alex - how does the field of view compare to dome, all else being equal? Size of tiles in comparison shots suggests to me the corrected port may reduce FOV. I know you said distances were variable, but I'd be surprised not to see some FOV compression with your test port. Depth of field and corner performance look promising though. Good luck with your project.

In Topic: New Canon 16-35 f/4 IS

29 August 2014 - 01:24 PM

No more in the way of conclusions than what I stated above. Have stayed with the 55mm port extension, which is what Seacam HQ recommends for the 16-35/2.8 II lens but not what Stephen Frink recommends for it. Looking forward to S.F.'s analysis of the 16-35 IS. 16mm is stretching it a bit for the superdome, which was designed for 18mm. Have not shot any other Canon made UWA rectilinear lenses so comparison not possible. The new lens is to replace my Sigma 20 and 28mm f/1.8 lenses. The new lens does appear to focus faster than these. Have you read Roger Cicala's reports? Here is a more recent shot. Done at f/8.

Tom

Tom - That's a really lovely shot ... congratulations!  I haven't done any testing on the new 16-35 F4, and have no reason to doubt the port extension suggestions that SEACAM Austria suggests.  I personally have the 16-35 II, and Canon Professional Services didn't have loaners on the F4 version last time I asked.  But, I'm off the road for a while now so maybe I can put the testing back on my radar. BTW ... the Superdome is a far better solution it appears (and we would expect) than the wideport.  Thanks for sharing Tom.


In Topic: Lens for mid-size animal portraits on 5D3

07 May 2014 - 02:42 PM

Between 8-15 and 100 macro I use 16-35 II a lot. If fish portraits the Sigma 50mm macro with either flat or dome port, depending on probable size of fish targeted.

The 16-35 II is quite useful, and the Sigma 50mm goes to 1:1, which is likewise handy and it is quite sharp. It is the only non-canon lens I use, and only because the Canon 50mm macro does not go to 1:1.

In Topic: Canon lens test - Trying to help a friend

23 January 2014 - 09:10 AM

Ok, so here is the final observation from this test, the optimal port extension for 24-70mm II F-4 L IS and also the +4 diopter, both on Superdome.  Note differences in corner performance and field of view:

 

Attached File  24-70II_PVL45_superdome_16.JPG   401.87KB   48 downloads

24-70_PVL45_superdome

 

Attached File  24-70II_PVL40_superdome_+4_10.JPG   418.19KB   36 downloads

24-70_PVL40_superdome_+4

 

If you need to work wide with this lens try it without a diopter, but still try to get F-8 or smaller for a working aperture to achieve reasonable corner performance.  For reef fish, accepting that you'll be tighter on the subjects, the +4 diopter is quite nice.