"Sigma 17-70mm F2.8-4 DC Macro OS HSM", which Ikelite port?

[ileiman]

I have a great desire to take my "Sigma 17-70mm F2.8-4 DC Macro OS HSM" lens underwater with my Canon 7D in Ikelite housing. I would use it on occasions where I'm not sure whether to put on a wide-angle lens (Tokina 10-17mm) or macro (Canon 60mm), so this lens would give me some flexibility during dive: almost wide-angle at 17mm, almost macro at 70 mm (1:2.8).
Unfortunately the Ikelite web page says for this lens:
"Lens diameter too large to operate in port system."

So, that is the official statement, but has anyone used this lens anyway?
And if yes, what are the results, and the recommended port to use?

The lens is of course too thick to fit the usual zoom gear sleeve, but there is a workaround to this. Another issue is that for the 8" Ikelite #5510.45 dome, the ideal modular port body that would support the whole zooming range would be something like 45 to 50 mm longer than the #5510.11 superwide body. But, there is no Ikelite body that fits this specification.
- There is the 5510.24 which is 38 mm longer than 5510.11, but this is a bit too short for zooming fully out to get macro.
- The next step is the 5510.28, which is 60 mm longer than 5510.11, but this is a bit too long, at the verge of vignetting at wide angle end.

Even with extenders, the closest you can get is the combination of
5510.16 + 5510.54, which is 51 mm longer than 5510.11 body.

The standard 6" dome 5503.55 looks like it could be the right length (about 44 mm more than 5510.11?), but a smaller dome might have issues with corner sharpness.

I started a thread about this in wetpixel, where the zoom ring workaround is explained:
"Sigma 17-70mm F2.8-4 DC Macro OS HSM", which Ikelite port? - Wetpixel :: Underwater Photography Forums

I also did test the lens underwater with #5510.45 dome + #5510.11 superwide body, the lens locked to 17mm, and result was very encouraging.

 

[BrettF]

ileiman,

It appears from your Scubaboard and Wetpixel posts that you have figured out an acceptable workaround for the lens zoom ring using the velcro strips. Seems like you have already taken the necessary measurements and know what you need. No one at Ikelite has used this lens underwater since it is not one we recommend due to the zoom incompatibility with our clamp and sleeve.

It seems from your posts that you are trying to find the "sweet spot" or optimal distance from the lens nodal point to the dome apex. This is not something we test for since zoom lenses have floating nodal points. It sounds like you have gotten close with the #5510.11 port body having the lens preset at 17mm. The simple answer would be to go with that setup and get a dedicated macro lens with a flat port, which will give you much better close-up results than the telephoto macro end of the 17-70mm lens behind a dome.

OR,

You could always go with the #5510.28 port body to utilize the full zoom range and find the "sweet spot", or sharpest corner to corner focal length zoom setting. Also, you can stop the camera down some to improve depth-of-field and possibly try a +2 diopter. Regardless, I would stick with the 8" dome.

Unfortunately with this lens, it will be trial and error, or finding users in the field with some practical experience.

Both the Tokina 10-17mm lens and Canon 60mm macro work well with our systems.

Regards,

 

[ileiman]

Brett, thanks for your comments.

One more question:
Is the 5510.25 port body (intended for Olympus/Zuiko 7-14mm) between the lengths of 5510.24 and 5510.28? It appears that 5510.25 comes with a special zoom sleeve for the Zuiko, but is there anything else special? So might the 5510.25 be worth trying if the Sigma 17-70 turns out to need something shorter than 5510.28, but longer than 5510.24?

I have both Tokina 10-17mm and Canon 60mm macro already, and they do work extremely well for either wide-angle or macro. Using these on a given dive commits you to take either WA or macro shots. So if you are shooting Pygmy Seahorses with the macro, you are out of luck when those Manta Rays suddenly appear. And while the Tokina is excellent for shooting Mantas, its not much use for the nudis and anything tiny.
So the Sigma 17-70mm would give flexibility, and is one of the few lenses that provide "almost WA-macro" capability in the same lens. It doesn't replace either true WA or macro of course.

 

[BrettF]

The #5510.25 port body is the same length as the #5510.24 port body. It is machined with a slightly larger inside diameter to accept the Olympus 7-14mm lens with it's custom zoom sleeve.

Regards,

 

[ileiman]

I suppose the most flexible solution is to get a 5510.16 port body, and all the extensions 5510.50, .54 and .58. That way I could try all lengths at half inch increments and see which works the best.
This is not of course the cheapest way to do it...

 

[BrettF]

That's probably the best way. You'll find "sweet spots" at different focal lengths with each extension.

Regards,

 

[ileiman]

I now found by experimentation the working port for this lens.
I am sharing the information just in case someone else needs the info.

The #5510.16 + #5510.54 (zoom body and 1.25" extension) with the 8" dome works very nicely at all focal lenghts. I just tested it at pool and it fully meets my expectations.
At 17mm it is a decent wide angle, and at 70mm it can do some sort of macro (1:2.8). The lens focuses at all focal lenghts and distances, and can focus to anything that keeps outside the dome. At very close distances the focus does hunt quite a bit, at longer distances focus locks fast. Images are sharp, even at corners and no serious chromatic aberration or vignetting at any focal length. The zoom ring hack with velcro tape works reliably.

Highly recommended as a general purpose "scouting" lens that offers a lot of flexibility. For really wide angle the Tokina 10-17 is of course no match, and for true 1:1 macro the EF-S 60mm macro behind a flat port is of course much better. The Sigma 17-70 is something to bridge between these two.

I also tested over/under shots at 17mm with the dome and it works somewhat for that too, however if the focus is sharp for the under-part, then the over part is slightly out of focus. Tokina 10-17 works much better for over/under shots.

 

[ileiman]

And here is "final proof" that the Sigma 17-70mm works really well with the Ikelite #5510.16 + #5510.54 + #5510.45 port system (8" dome with basic zoom body and 1.25") extension.
You can shoot a Manta Ray at 17mm setting (wide angle):

or you can shoot a Pygmy Seahorse at 70mm (Macro) setting:

Or something in between (21mm)

And you will get razor sharp images with no corner softness or chromatic aberration issues.
This is a very versatile lens & so I used it most of the time on 38 dives at Raja Ampat live-aboard trip in Indonesia. You need some velcro-tape to attach the zoom ring inside Ikelite port, but this is a work-around that seems to work really well.

More pictures here:
https://picasaweb.google.com/ianleiman/Indonesia2011Selection1?authkey=Gv1sRgCLGr0Ju3z8L_qQE&feat=directlink