Canon DSLR Lens Choice

Those are some great images. I've gotten close to a sea turtle once, but have only seen rays off in the distance, and haven't seen dolphins at all.

That said, a 600 x 400 image isn't going to show any limitations of a lens except for distortion, which you can fix in photoshop. Blur and chromatic abberation tend to be in the 2-3 pixel range at worst in a 3456 x 2304 image, and will completely vanish when each pixel in a 600 x 400 image represents 5x5 pixels in the original.

You tend to see the difference when viewing larger versions. Large prints, or viewing the image full-screen on a good sized monitor. Prints will tend to be more demanding even at the same view size.

Of course, I don't know what your exposure conditions were - the EF-S 18-55 won't be that bad if it's stopped down to f/8.

- Gus

In regards to the small view finder: with the SeaTool and Ses & Sea housings and several others the Inon 45 degree view finder can be put on it. This helps greatly with getting more out of the view finder.

In certain circumstances AF will hunt a lot underwater, so manual focus can be a tremendous advantage. ..

Hi. I am new to taking pics underwater. I opted to go for a 50mm 1.4 (for canon 350d, 6" dome port) because I thought having a fast lens would benefit in low light conditions. Though I've experienced that it does not hunt underwater, rather it does not (auto) focus at all. No matter how close or far my subject is, the shutter wouldn't release because it couldn't focus (at one shot mode). Hence I went back to my trusty kit lens.

Is there a way to find out which lenses have similar problems, so i know which ones to stay away from? Or would the 50mm still be usable?

the trouble you had was that the lens couldnt focus close enough on the virtual image of the dome. (distance at more or less twice the diameter of the dome). You can do a search for dome port theory, or virtual image to find out more about this.

For the 50-100mm range, a dome port is not that usefull, as you will losse magnification.

Hi. I am new to taking pics underwater. I opted to go for a 50mm 1.4 (for canon 350d, 6" dome port) because I thought having a fast lens would benefit in low light conditions. Though I've experienced that it does not hunt underwater, rather it does not (auto) focus at all. No matter how close or far my subject is, the shutter wouldn't release because it couldn't focus (at one shot mode). Hence I went back to my trusty kit lens.

Is there a way to find out which lenses have similar problems, so i know which ones to stay away from? Or would the 50mm still be usable?

Yes, that is to be expected. If you look at the specs for that lens, you'll see that it is not designed for close focusing. Minimum focus distance is 1.5 feet. The dome creates a virtual image that the lens must focus on, and normally, the apparent distance to that image is on the order of several inches. Your lens would work fine behind a flat port. Either that, or you need to put a diopter on it. I'm not sure how useful that lens is anyway when paired with the dome port unless you really need to do low light photography. If you're looking to do macro work, I'd suggest buying a proper macro lens and putting it behind a flat port.

Mike

Thanks for the inputs.. The close focusing distance was one of my hunches, though I didn't expect that even though my subject was way far off that it wouldn't be able to focus..

Will read around regarding this.

Thanks again.

Hi,

I am using a Canon 40d with ikelite housing and a 50mm/f 2.8 lense. I am thinking of buying a wa lense now. is it better to get a 10-22 or to get a 18mm fixed?

Thanks

Ajith

I am using a Canon 40d with ikelite housing and a 50mm/f 2.8 lense. I am thinking of buying a wa lense now. is it better to get a 10-22 or to get a 18mm fixed?

I have the EF-S 10-22, and I think it's a great lens. I've gotten some really great land photos with it, and there were definitely times when I wanted the full 10mm field of view.

Underwater, I found I wanted 22mm almost all the time, so a fixed focal length (prime) 18mm lens isn't very restrictive. However, I've only been on 26 dives now with a camera, and only two of those with the 10-22, so take that with a grain of salt.

Who makes a 18mm prime for the Canon mount, though? Canon and Sigma make 20mm lenses, and Tamron makes a 17mm, but I don't know of any 18mm primes. A quick read of the reviews indicates none of the lenses I mention are very good, which kind of surprised me. You'll get better sharpness and chromatic abberation from either the EF-S 10-22mm or the EF 17-40 f/4 USM L.

I'd get one of those two lenses and a 8" dome port. Which you get depends on what else you intend to do with the lens. If you don't currently have a zoom in the 17-40mm range - which is a very useful range on a 1.6x crop camera, equivalent to 28-64mm - I'd get the 17-40. Otherwise I'd get the 10-22, which I mentioned that I own and like very much.

- Gus

Hi. I am new to taking pics underwater. I opted to go for a 50mm 1.4 (for canon 350d, 6" dome port) because I thought having a fast lens would benefit in low light conditions.

Others have explained the issues with dome ports and focus. To this, I want to add that as a beginner, I was focused on low-light performance as well before I actually dived with the camera. Certainly it's something I think about a lot on land.

What I found was that low-light performance is of little benefit except on actual night dives. Sure, it's darker at 80' than at the surface during the day, but it's not that much darker. The bigger issue is that you want your strobe to provide much of the light in the photo, not ambient light, because you want to see the subject's color, not washed-out blue. So you end up forcing smaller apertures just to force more light from your strobes.

Even at night, when for all practical purposes your strobes are your only light source, you still want to be somewhat close to your subject, and hence you'll still have plenty of light from your strobes for f/4 or smaller.

- Gus

Hi,

 

I am using a Canon 40d with ikelite housing and a 50mm/f 2.8 lense. I am thinking of buying a wa lense now. is it better to get a 10-22 or to get a 18mm fixed?

 

Thanks

 

Ajith

For underwater use, I strongly recommend getting the Tokina 10-17 fisheye lens instead of the Canon 10-22. I have both lenses. The Tokina is the only one I use underwater now. It is difficult to get sharp corners with the 10-22. The 10-17 fisheye is crisp.

For underwater use, I strongly recommend getting the Tokina 10-17 fisheye lens instead of the Canon 10-22. I have both lenses. The Tokina is the only one I use underwater now. It is difficult to get sharp corners with the 10-22. The 10-17 fisheye is crisp.

I have difficulty understanding this, since 1) I've not noticed much corner softness with the 10-22 and 2) switching to a fisheye lens seems like a huge change to make just because you feel the corners are a little soft. The curved distortion of a fisheye seems like a far, far more distracting effect than a little softness. It's such a huge effect that you're really comparing apples and oranges.

- Gus

I have difficulty understanding this, since 1) I've not noticed much corner softness with the 10-22 and 2) switching to a fisheye lens seems like a huge change to make just because you feel the corners are a little soft. The curved distortion of a fisheye seems like a far, far more distracting effect than a little softness. It's such a huge effect that you're really comparing apples and oranges.

 

- Gus

Hey Gus.

That's the beauty of a fisheye underwater. Note, it is NOT a circular fisheye. With no straight lines as points of reference, the "curved distortion" is not really an issue. All these photos are with the Tokina (yes, including the topside photo!):

That's the beauty of a fisheye underwater. Note, it is NOT a circular fisheye. With no straight lines as points of reference, the "curved distortion" is not really an issue. All these photos are with the Tokina (yes, including the topside photo!):

Actually, I really notice the curvature of the background in the ray photos. It's an obvious straight line that's been distorted. But I really like them anyway, so maybe it's not as important as I'd think.

- Gus

As for rectilinear vs. fisheye - it is really a question of taste - even underwater. Yes, the lack of straight sharp "horizons" lacking in many underwater photos makes the fisheye distortion less noticable - and the bottom/watercolums "horizon" curvature is often seen as just a natural "slope". However, some people really do NOT like the fisheye look. I am one of those and I find the fisheye distortion very unattractive. I have fellow shooters who have absolutely no problem with images with fisheye distortion and even consider it attractive. So there you go, you have to decide if it rubs you the right or the wrong way. And do also remeber that the rectilinear Canon Ef-s 10-22mm will give you distortion as well, it just doesn't give you the round bulging FE convex distortion.

If you are not a fan of Fish Eye then the rectilinear Canon 10-22mmm is really a reasonable choise, especially if you consider the alternative of the much more expensive rectilinear Canon 14mm prime. You get the ability to focus extremely close, and you have the flexibility to zoom all the way to 22mm which is great when that dolphin just won't let you any closer...

Yes at 10mm the corners can be a bit soft, and if that is really truly something that bothers you, then beware. I personally never lost any sleep over soft corners and am somewhat amused at all the attention this particular issue always gets. As I see it, for one, due to composition, expecially CFWA, most "corners" contains either blue water or some bottom substrate that is not part of the subject. Secondly, although shooting at 10mm is nice, I seldom find myself shooting all the way at 10mm.

If I could justify it, I would go with the rectilinear 14mm, but the 10-22 is a pretty darn good alternative.

The downside to this lens is that it has the EF-S mount if you are going to shoot a full frame one day.

I personally think this is a really funpacked lens and I just can't get enough of it both over and under the surface.