Canon 17-40 softness at 17mm using 8 inch dome port?

Hi

Moving more into wide angle work using a subal set up for the 5Dmk2 and 1D series cameras and need some help regarding appropriate dome ports and WA lens. I currently have in my arsenal the canon 17-40 and Sigma fisheye.

I have read on several threads the edge softness of the 17-40 when shooting at 17mm and using a 8 inch dome port with a full frame sensor.

Will moving to a 9 inch or 12 inch dome port solve this issue?

Or, is a better option to change to a different lens (ie 24mm) and still use the 8 inch dome port.

I have yet to purchase a dome port and am trying to determine which is better for my requirements.

Obviously, using a 1.3 crop camera (1DEMK3) alleviates these issues a little, but using the 1DSMK3 just brings them back!

Help appreciated. Thank you…..Iain

Hi Ian,

It's interesting to watch your progression through this setup - something a lot of us went through over the last few years.

Your next stop should be Stephen Frink's exhaustive test sequences - which have been reproduced here and are also available on his blog. He tested using the Seacam Superdome which is a BIG dome - and the 17-40L performance doesn't improve much.

The basic rule w/ that lens is that if you can't shoot it at F8 or even F11 you will have soft corners. If you really need something sharp in the corners, none of the zooms are terrific but the 16-35II is the best. Good alternatives are the Tokina 17mm and the Canon 24mm F1.4L

Cheers

James

at shorter focal lengths the edges are so soft on the 17-40 wide open as to make it completely unacceptable for me - on land. additionally, this, and most other wide angle zooms are assymetry (i assume from mechanical tolerances) which may make one side worse than unacceptable. after a warranty trip to Canon mine is now sort of usable at f5.6 and shorter focal lengths but James is absolutely correct that this is really an f8 lens at shorter focal lengths

Thanks James and Stever - good input there!

Yes, I feel this has all been done before and will be done again. I already have looked at Steven's website (beat you to it)

Talking with backscatter they recommend the 8 inch subal dome with 2x diapoter if using the 17-40. BTW, my 17-40 is quite good even at open apertures (on land).

Does the 2X dipoter solve the issue - or is it only marginal??

It seems as Stever and you have stated (as well as others) that the 17-40 at 17 is indeed not the best lens to use U/W unless shooting at f8 plus (and the obvious higher ISO rating (which is possible on the 5DMK2 and 1D M3 and mk4 bodies.

I'm actually debating the 24mm type 2 1.4 prime as we speak.

Is the 24 1.4 soft at the edges using the 8 inch dome????

I guess I can either purchase a 24mm 1.4 type 2 prime OR the 16-35 2.8 type 2 zoom.

Which would be the sharper lens with the 8 inch dome?

Backscatter say I will still need a 1X dipoter with the 16-35.

Thanks for your help......Iain

I have the same problem, have been using a 8" dome on a Aquatica with mt 5D + 17-40 and the corner shrpness is awfull, got a BW

+2 diopter but havent made some serious tests yet. Will keep you posted.

Nuno.

I have the same problem, have been using a 8" dome on a Aquatica with mt 5D + 17-40 and the corner shrpness is awfull, got a BW

+2 diopter but havent made some serious tests yet. Will keep you posted.

 

 

Nuno.

Thanks. I'm thinking of just upgrading to the 16-35 type 2 and not having the hassles! My 17-40 is great on land, but it seems it's not suitable for U/W use - so an upgrade maybe in order

using the +2 dioptre will reduce the angle of view of the wide zooms, so you end up cropping out the blurry corners

The 16-35II beyond f8 behind Seacam Supedome has been the only ay I've been able to get reasonable corners on full frame.

using the +2 dioptre will reduce the angle of view of the wide zooms, so you end up cropping out the blurry corners

 

The 16-35II beyond f8 behind Seacam Supedome has been the only ay I've been able to get reasonable corners on full frame.

Darren - thanks for your input!!

Do you recommend the 24 1.4 type 2 or the 16-35 type 2??

I am conscious that the 24mm is probably not wide enough, despite being an awesome land wide angle prime! Iain

Darren - thanks for your input!!

 

Do you recommend the 24 1.4 type 2 or the 16-35 type 2??

 

I am conscious that the 24mm is probably not wide enough, despite being an awesome land wide angle prime! Iain

Iain, I'm a zoom fan.... so the 16-35II for the types of things I do.

Iain, I'm a zoom fan.... so the 16-35II for the types of things I do.

Cool Darren thanks. Appreciate your input....Iain

Say Darren, what Canon body you using U?W at the moment? Iain

Mainly the 5dmkII in Aquatica.

On some jobs, if I need two lenses at hand I'll add my older 1DsmkII in Seacam.

I still sometimes grab the cropped sensor Nikon D200 kit... the close focus capability of the my Sigma lenses (10-20 and 17-70) makes them sweet to use....

Mainly the 5dmkII in Aquatica.

 

On some jobs, if I need two lenses at hand I'll add my older 1DsmkII in Seacam.

 

I still sometimes grab the cropped sensor Nikon D200 kit... the close focus capability of the my Sigma lenses (10-20 and 17-70) makes them sweet to use....

Cool - I ask as I'm about to upgrade my 5D. Still debating the Subal with a 5DMK2 or a Subal with the 1DMK4 which can also take the FF 1DSMK3 - decisions decisions.....

Cool - I ask as I'm about to upgrade my 5D. Still debating the Subal with a 5DMK2 or a Subal with the 1DMK4 which can also take the FF 1DSMK3 - decisions decisions.....

hopefully the 1DsmkIV will fit too.

hopefully the 1DsmkIV will fit too.

Backscatter seem to think so, although they are not too sure yet!

I think I'll be springing for the 5DMK2 in a replacement Subal housing - as the housing is smaller and lighter in weight - easier to use for macro and for carrying on flights O/S! Also, the new 1DMK4 Subal housing is a tad shy of 9K!! We are almost entering Seacam territory here Darren...The 5DMK2 & a new housing is the the same as just a 1D housing....

small is good, affordable is good.

stills... 1DmkIV's 10fps would be nice on the odd occasion, but wide is a problem with the 1.3x crop sensor.

video... only thing you won't get in the 5Dmkii is the 720p @50/60fps

small is good, affordable is good.

 

stills... 1DmkIV's 10fps would be nice on the odd occasion, but wide is a problem with the 1.3x crop sensor.

video... only thing you won't get in the 5Dmkii is the 720p @50/60fps

True, but the video on the 5DMK2 is still pretty good - OK I concur not as good as the MK4.... But, you cannot have everything - and if you REALLY want video you probably should be using a dedicated HD video camera U/W. Still thinking - too much thinking about whether to go with the 5DMK2 or the 1D series housing - I need to make a decision and move forward...

Will grab a 16-35 T2 in the morning locally. My shop has one on hold for me... Think I'll donate the 17-40 somewhere...

Nice to chat Darren, It has been quite sometime - many many years in fact since we last spoke Iain

I think the 5DmkII video is the best quality of the bunch, but the faster frame rates available on the newer models is attractive.