Canon 28-105

I tried out my canon standard 28-105 zoom in my flat port thinking 'it wont fit', but it did! Has anyone tried this combo before?

Do a search for scubadru and that lens. He has posted some very nice images with the Canon 28-105 f3.5-4.5. Don't know if he was using a flat or dome port and whether he was using a full frame or crop-sensor camera.

On a full frame camera like the 5D I think 28mm is getting close to an angle where you start needing the dome. You can only find out once underwater (or in a bath tub). The other concern is vignetting at the 28mm setting with a flat port. You can check the later topside. I'm planning on using a Tamron 28-75mm f2.8 behind a flat port and don't see vignetting. Because I'm using a 20D with 1.6x crop, 28mm is really 49mm in 35mm equivalent, so that one should be fine without dome (or so I hope).

Bart

I tried out my canon standard 28-105 zoom in my flat port thinking 'it wont fit', but it did!

So does it fit through the whole range of zoom and focus?

It'll be interesting to see how the corners stand up at full 28mm. Bear in mind that to use it in a dome you'll be needing a dioptre because it's not much of a close focus lens. If you want any help getting a zoom gear on it, give us a shout.

Martyn

With the lens racked out to 105mm it's still fits behind the flat port and focused no problem. I've not tried it with the dome underwater, but if i did i would need the dioptre as you say. To be honest Rattus, I'm happy with it set at 105 and use it as a 'psuedo' macro lens until i can afford another 105 macro.

I know someone running the 24~105L lens behind a large dome who is very happy with it! Don't see why the 28~105 should be any different - try it behind as large a dome as you can (with appropriate extenders) and you might find that it is useful as an GP lens if not wondrous for specifics.

Out of interest, what dioptre would you chaps suggest for the 28-105 behind an Athena dome? +2, +4?

Rattus, zoom gear wise what would you recommend. I noticed you extolling the virtues of the long tube Athena jobbys in previous posts somewhere.

Well, Jolly's probably your man to answer the dioptre question, but I'd be surprised if a +2 doesn't basically sort you. That'll make 50cm look like infinity to the lens, and your Athena port will put infinity at about 45cm. Sounds about right to me and my thumb.

As for zoom gears, I'm wondering about compiling a list of lens dimensions so we can work out which gears will fit which lenses. Could you measure up your 28-105? I need the diameter at the zoom ring and the distances from the lens mount to a) the nearest edge and B) the furthest edge of the zoom ring.

It would also be useful to know how much the AF/MF switch sticks out of the side of the lens barrel.

Cheers,

Martyn

Merry Christmas everyone!

Rattus, I'm well impressed with your lens picture with the dims added. Most professional sire.

My 28-105 don't look like that though! It's the USM version, but i will measure and let you know. Many thanks for the info. Much appreciated.

Oh right, is yours the f/3.5-4.5 rather than the f/4-5.6? The 3-4 has the zoom ring at the front and the focus ring at the back, nearer the camera body - oh, and has a metal mount.

Martyn