Beamshot - What lens should be used ?

Tony_J_Ross said:

G'day gang,

If we're going to submit beamshots at 100 ISO F4 6seconds with WB at Daylight, what kinda lens should we be using as a standard ?

Very few camera's in circulation have 28mm or wider, so are we standardising to 35mm or 50mm ?

I've got super wide (16mm) which is great to capture fisheye like beamshots but very deceptive for comparison with other people's beamshots.

Tony

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I tend to use 50mm equiv on my 40d. I.e: It is a 1.6 cropper so 31mm

The theory go's that 50 mm is roughly equivalent to the field of view seen with the naked eye so it makes sense.

How can you tell when you're at the "50mm equivalent"? I just looked up the specs for my aging canon A60; it has "a zoom lens with a 35mm equivalent focal length of 35mm - 105mm". But no way to indicate exactly where I am in that range. I've tried to take some beamshots using the MTBR standard settings without zooming in at all, but they come out looking too far away. But that makes sense now, seeing that was at 35mm.

A while back someone posted a cool way of overlaying a beam width scale onto the beamshots, but I could never wrap my head around how it was going to work on different cameras. I guess the 50mm equivalent is the answer. But it seems, with my camera anyway, that it's just going to be a guess?

JZ

JimZinVT said:

How can you tell when you're at the "50mm equivalent"? I just looked up the specs for my aging canon A60; it has "a zoom lens with a 35mm equivalent focal length of 35mm - 105mm". But no way to indicate exactly where I am in that range. I've tried to take some beamshots using the MTBR standard settings without zooming in at all, but they come out looking too far away. But that makes sense now, seeing that was at 35mm.
JZ

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Your A60 uses a 1/2.7" sensor size, so your "equivalent crop factor" is 6.44:
http://en.wikipedia.org/wiki/Image_sensor_format

Just take the focal length readings your camera gives you and multiply by 6.44, and you have your 35mm equivalent framing.

cosmoworks said:

Just take the focal length readings your camera gives you and multiply by 6.44, and you have your 35mm equivalent framing.

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Thanks for the reply cosmo, but I'm not really following Where would I see the "focal length readings"? When I zoom in and out there is nothing on the display indicating the zoom level (other than the image getting bigger I know the short end of the zoom is 35mm equiv. and the long end is 105mm equiv. And when you say "multiply by 6.44" is that something I'm doing with photo editing software, or ???

Sorry for my digital photography ignorance. back in the days of film I did a lot of photography, with very good results (if I do say so myself :blush: ) But with a digital camera my results have been generally terrible. (a better camera would probably help, someday).

JZ

JimZinVT said:

is that something I'm doing with photo editing software, or ???

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You probably have to download the image to your computer first, then check the EXIF data of the file to see what the focal length recorded at (right click > properties > details.. if you're on a PC).

JimZinVT said:

When I zoom in and out there is nothing on the display indicating the zoom level (other than the image getting bigger

JZ

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I think we got a bit technical for a P&S camera. My suggestion would be to adjust the zoom on the camera so that it matches as closely as possible the field of view you have with the naked eye. Just stand there and look at the scene and figure out what is visible at the extreme edges of your vision and then zoom in/out to match.

Happy shooting!

Good answer Salty.
Many, many moons ago when I was younger and we all used film we were tought to shut one eye and look over the top of the camera, look back through the camera.... keep doing it until both views were the same. That's 50mm and it's the view from one eye to compensate for the fact that a camera only has one lens.