Add-on lens for the Sony DSC-W1

Greg_Mitch · 06-29-2004, 02:58 PM

I have read that this accepts 30mm conversion lens if I have the adapter. So will this only take Sony brand or can I find any lens that is 30mm and has threads?

Also, if I would purchase a 2.6 telephoto conversion lens would this be multiplied by the cameras already 3x optical zoom to give me a pretty good 7.8x optical zoom?? That would be really cool.

Thomas Newton · 06-29-2004, 04:38 PM

Quote:

Also, if I would purchase a 2.6 telephoto conversion lens would this be multiplied by the cameras already 3x optical zoom to give me a pretty good 7.8x optical zoom?? That would be really cool.

Telephoto converter adapters have a fixed magnification -- usually 1.4x or 2x. The optical zoom range will remain at 3x whether you have the telephoto converter lens on or off.

What will change is the magnification at every part of the 3x range. For instance, if the camera's normal lens range (in 35mm terms) is 35 mm to 105 mm without a teleconverter, it will be 91 mm to 273 mm with the one you mention.

You'll need to add/remove the teleconverter to switch from wide-angle/normal to telephoto zoom ranges.

Greg_Mitch · 06-30-2004, 05:48 PM

If you say it is from 35mm to 105mm(in optical zoom this is like 1x to 3x correct?) then saying putting a telephoto lens on would make it 91mm to 273mm (in optical zoom this would be 2.6x to 7.8x optical zoom right?) I guess I don't understand when you say it only zooms in on every part of the 3x optical zoom. Isn't that the same thing as saying 3x(multiplied by 2.6x) gives you 7.8x zoom?

Thomas Newton · 07-01-2004, 11:01 AM

Quote:

If you say it is from 35mm to 105mm (in optical zoom this is like 1x to 3x correct?) Focal length ratio = optical zoom factor, thus 105 mm.

I don't know where your camera's zoom range begins, but it's likely that in 35mm film terms, it's somewhere between 28 mm and 38 mm. A 3x optical zoom factor with a 35mm-equivalent lower focal length would imply a 105mm-equivalent upper focal length.

Quote:

Isn't that the same thing as saying 3x(multiplied by 2.6x) gives you 7.8x zoom?

A zoom lens that had a 7.8x zoom range would give you the equivalent of a (35 - 273) mm range without the need to change lenses, or to attach and detach telephoto converters. A teleconverter may give you a 7.8x total range, but you will need to attach/detach the teleconverter as you cross the middle of it.

Man-Fai Wong · 07-01-2004, 01:20 PM

Beyond what Thomas said, I would add the following (not already addressed):

1. It's very likely that you can find other 3rd party lens converters that work also. However, there could be quality issues, especially w/ very cheap, no frills converters, as well as issues w/ vignetting. Not too sure, but seems like Sony converters tend to offer some of the best quality optics for digicams. That certainly seems so for their larger converters that can be used on digicams like my Canon G3. They are usually quite hefty though (as is usually the case w/ the best optics) and cost a good sum more than the competition. If you're looking for 3rd party glass, Olympus seems to offer the best quality after Sony. But I'm speaking based on research for larger digicams like my G3. This might not hold quite as true for your Sony W1. Other noteworthy brands include Kenko, Raynox and Tiffen although they are usually inferior to Olympus. Canon also makes pretty good converters that probably fall between Olympus and those others.

2. If you go 3rd party (or a Sony one not designated for the W1), make sure it's compatible first or have good return policy. Vignetting is a real issue when mixing and matching converters as is a couple others like optical distortions regardless of the brand and quality of the optics. There are design issues here beyond just quality of optics and matching thread size although usually larger converters will more likely work than smaller ones.

3. About the useable/effective zoom range, you should note that you may not be able to use the full 3x range w/ a tele converter attached. There is usually some vignetting issue at the wide end of the range. Also, optical quality and/or AF performance may suffer a little as you zoom out from full tele end besides the vignetting issue. These issues will also vary based on the actual converter you use (and maybe the adapter as well if you use a 3rd party one).

For example, I can only use my G3 + Canon 1.7x tele converter effectively for the ~2.5-4x zoom range (multiplied by 1.7x). If I zoom out to wide angle, I run into serious vignetting and get the tunnel/telescope vision effect.

4. For some places to shop, you might try B&H (www.bhphotovideo.com) or this popular online dealer Filter Connection (www.2filter.com). Never actually used the latter, but I hear good things about them and they seem to offer pretty good selection although not sure about your W1.

_Man_

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Greg_Mitch · 07-01-2004, 04:10 PM

Thank you for the help on the questions and this does help clear things up a bit. I may get the 2.6x telephoto conversion lens if I think I will use it. I would like to get a nicer "SLR" type digicam but I don't have the budget and also don't want to carry one around right now. Thanks again.



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