apples-to-apples wide angle comparision

Hi all,

I need some apples-to-apples comparison on two different setups. If I had a P&S with a 35mm lens and added the Inon UWL-100 to it for wide angle, what would be a valid comparison in the housed DSLR world? A 18mm with a flat port? 14mm? 14mm with a dome?

I'm thinking about the jump to the DSLR world and I'm just creating a little internal pro/con list for myself. I'm of the opinion adding a wet wide angle to a P&S with 35mm focal length will probably result in about 20mm effective.

This would create a side question: How many out there are shooting with something similar to a 18-55m kit lens in a flat port? Links to some sample pics I can see?

thanks!

JP

Look up the angle of coverage in your instruction manual. That should give you the information you need.

For a comparison the classic Nikonos 15 mm has a coverage angel of 94. The 17 mm end of the 10-17 FE DX also has a similar angle of coverage.

The 17 mm end of the Nikon 17-55 is 80 (degrees)

The 12 mm end of the Nikon 12-24 is 100 degrees.

I believe Inon makes several wide angle converters. Some of them can achieve wide angle coverage similar to what you can achieve with a dSLR.

You will have to deal with shutter and autofocus lag that you don't with a dSLR.

It is harder to compose a photo with a consumer point and shoot vs. using the optical viewfinder on a dSLR.

You don't shoot wide angle with a flat port. Not if you want good results.

The equivalent in 35mm terms is about a 20mm lens behind a dome port.

Cheers

James

I have tried my 18-55 kit lens behind a flat port.

Here's the link

My Sigma 15mm FE is a little wider than my Coolpix 5000 (28mm) with wide adapter.

Here's that link

This is a photo taken at the 10 mm end of the tokina 10-17 FE. The nose of the Stellar Sealion is presses into the dome. At this end you have 160 angle of coverage and the lens can focus on the dome.

By way of contast this photo of Orcas was taken with the 17 mm end of the 17-55. The photo suffers as this lens is not wide enough for the subject. Though not a problem in this photo this lens does not focus near as closely.

I had switched to this lens thinking that we wouldn't see large subjects. The 17-55 can be very good for small to medium size subjects. I had expected to shoot eels, and small fish at feeding stations.

Great responses, thanks very much. Andrew's and Dave's photos with the 18-55 and 17-55 respectively were very instructive. Also the comparison pics of Andrew's Coolpix with WA adaptor compared to the 15mm sigma.

It seems having a 6" dome port for the 18-55mm and perhaps a 60mm macro would be a good starting point? Having a 10-17 or 12-24 would be cool at some point, along with 8" dome, 100mm macro, etc, etc. Babysteps.

I've also seen some posts on this board suggesting the Sigma 17-70mm macro is a good "entry level" lens and also fits in a Ikelite 6" dome port.

Further comments are appreciated.

Thank you,

JP

On a DX camera such as the D200 I consider 17 mm (non FE) to be just barely in the wide angle zone. Your 18-55 would be good for medium size shots. You also need to look at how close the lens focuses. Some of those kit lenses do not focus that closely.

For true wide angle on a DX camera you will need either a FE or a lens with a 35 equivalent of at least 16 mm at the wide end. In the end though, it will all depend upon what you are trying to shoot and your water conditions.