Sigma 17-70mm focus issues

After getting several recommendations, I picked up a Sigma 17-70mm lens (the old one - non HSM/OS) for my Nikon D200 in Subal housing. I am still doing trials with it to get it tweaked just right, but so far am having difficulty getting it to focus on anything past about 5 feet away. It is currently behind an 8" dome, with EXR-33 extension ring, and +2 dioptre. Close focus is great, but I really got this lens to shoot larger subjects like turtles, groupers, and sharks that are not within arm's reach. Not sure how useful this lens is going to be for WA work if I cannot focus on anything closer than 5 feet. I know the dioptre is an issue here with the infinity focus, but I was hoping it would behave a little better than this! Going to keep playing with it and maybe try behind the flat port.

Anyone else run into this problem?

try without the dioptre and report back

try without the dioptre and report back

I agree or try a +1 diopter

After getting several recommendations, I picked up a Sigma 17-70mm lens (the old one - non HSM/OS) for my Nikon D200 in Subal housing. I am still doing trials with it to get it tweaked just right, but so far am having difficulty getting it to focus on anything past about 5 feet away. It is currently behind an 8" dome, with EXR-33 extension ring, and +2 dioptre. Close focus is great, but I really got this lens to shoot larger subjects like turtles, groupers, and sharks that are not within arm's reach. Not sure how useful this lens is going to be for WA work if I cannot focus on anything closer than 5 feet. I know the dioptre is an issue here with the infinity focus, but I was hoping it would behave a little better than this! Going to keep playing with it and maybe try behind the flat port.

 

Anyone else run into this problem?

I am using an the older HSM, but non OS lens in a Nexus (Anthis) D80 housing with 170 mm port and 40 mm extension. No diopter! No close focus problem. Have you used your lens for top side shooting? For any Sigma lens, test to spec. first. Is the lens used?

Bob

After getting several recommendations, I picked up a Sigma 17-70mm lens (the old one - non HSM/OS) for my Nikon D200 in Subal housing. I am still doing trials with it to get it tweaked just right, but so far am having difficulty getting it to focus on anything past about 5 feet away. It is currently behind an 8" dome, with EXR-33 extension ring, and +2 dioptre. Close focus is great, but I really got this lens to shoot larger subjects like turtles, groupers, and sharks that are not within arm's reach. Not sure how useful this lens is going to be for WA work if I cannot focus on anything closer than 5 feet. I know the dioptre is an issue here with the infinity focus, but I was hoping it would behave a little better than this! Going to keep playing with it and maybe try behind the flat port.

 

Anyone else run into this problem?

I have used this lens for years. As has already been said, no need for any diopter. This lens focuses extremely close and a cheap piece of glass in front will only degrade the image and not allow you to focus at distance.

I'm thinking to get one too. Just wonder why no one use the newer vision?

After getting several recommendations, I picked up a Sigma 17-70mm lens (the old one - non HSM/OS) for my Nikon D200 in Subal housing. I am still doing trials with it to get it tweaked just right, but so far am having difficulty getting it to focus on anything past about 5 feet away. It is currently behind an 8" dome, with EXR-33 extension ring, and +2 dioptre. Close focus is great, but I really got this lens to shoot larger subjects like turtles, groupers, and sharks that are not within arm's reach. Not sure how useful this lens is going to be for WA work if I cannot focus on anything closer than 5 feet. I know the dioptre is an issue here with the infinity focus, but I was hoping it would behave a little better than this! Going to keep playing with it and maybe try behind the flat port.

 

Anyone else run into this problem?

This is underwater? On land a +2 dioptre will stop you focusing on distant objects. I use this lens with a +3 dioptre underwater and have always been able to focus on distant subjects.

I'm thinking to get one too. Just wonder why no one use the newer vision?

I think most of the shooters who want this lens already have one. The newest version HSM with OS has only been out for a relativity short time.

Bob

Alex,

Excuse my ignorance but why do you choose to use a +3 diopter? Or any diopter for that matter? I use this lens in a 6" Aquatica dome port and my untrained eye is apparently happy with the results. It could be that I am guilty of the "Ignorance is bliss" syndrome.

TomC

I have found Alex's rational for utilizing a diopter with this lens in another thread.

I have used the Sigma 17-70mm with the 500D, a standard single element +3 dioptre and with no dioptre. My Sigma 17-70mm is the non-HSM, pre-stabilizer variety.

It works with all three. I did not do any objective testing - just tried different combos on different dives. I was happiest with the results from the single element +3 dioptre - so I continue using that for all my dives with the 17-70mm.

It appears to be just personal preference.

TomC

Thanks to all for your feedback. To update on this issue....I dove the setup this weekend with no dioptre. After doing more thorough tests in the pool, both with and without the dioptre, I decided I was not doing myself any favors by keeping it on. Distance focusing was great, as was focusing on objects that were directly in contact with the dome port.

For general reference, this lens is a bit noisy, although not to the point of distraction. It also seemed difficult at times to tell if the image was in focus while looking through the viewfinder and housing, although the images looked okay on the computer afterwards.

I chose the older lens version due to size limitations. The newer models are just too beefy to fit in my housing or to get a gear around.

Might play around with this lens in the flat port on the next dive, just for schitzengiggles.