IR Beam Macro Lens

Hello,

 

I know nothing about photography, but purchased a used Rebel 2000 on

Ebay with the zoom lens. When I received it had a lens screwed on to

the end of the zoom lens that is called I.R.Beam. I assume it is

infa red as inside the lens looks red. It says on the outside

MacroS7/52 Japan and in the rim IR Beam super wide High Resolution

Macro 0.42xAF. This looks like a lens and not a filter. I have spent

an enormous amount of time, on the net, trying to figure out how you

are suppose to use this lens, without any success. The articles I

have found on IR don�t really talk about IR lenses. Would you please

tell me how to use it, or point me in the right direction.

 

Thanks so much,

Jackie

Okay, I'm afraid you appear to be a bit confused about a few points here. First, you say you bought a Rebel 2000 with "the" zoom lens. Which lens is it, exactly? The Rebel 2000 does not always ship with the same lens type every time. The lens should be marked by a sort of code which identifies the manufacturer and various optical and mechanical properties of the lens. eg: Canon EF 28-80 4.5-5.6 III, say.

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Second, infrared refers to a specific type of electromagnetic energy which cannot be seen by the human eye. Infrared is not red light that we can see, though devices which produce infrared energy also often produce visible red light as well.

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There is no such thing as an "IR lens" per se. There are types of film which are sensitive to infrared energy and there are many complex related issues related to this, but this has nothing to do with just the lens. (yes, I'm glossing over a bunch of minutiae here like IR correction and stuff)

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Third, the removable device on the end of your lens sounds like a wide-angle adapter. This is an optional optical accessory which bends the light coming into the lens and lets you take wide-angle photographs. These devices often have removable lens accessories on the back that let you take closeup photographs as well. Unfortunately the optical quality of these adapters is generally really poor and so they're unsuitable for much more than fun snapshots. I have a brief review of such an adapter here:

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<A HREF= "http://photonotes.org/reviews/fisheye-adapter/" > http://photonotes.org/reviews/fisheye-adapter/ </A>

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I'm puzzled as to why this adapter would be red, though. You say the glass itself is red? Perhaps it was tinted red to block some visible light so it could be used with an infrared-sensitive camcorder or something.

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I also have a beginner FAQ which may be of interest to you:

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<A HREF= "http://photonotes.org/articles/beginner-faq/" > http://photonotes.org/articles/beginner-faq/ </A>

Jackie,

 

Why not just ask the seller you got Rebel/lens from?

 

Cliff

Hi Cliff,

 

It was a pawn shop, they said they didn�t know anything about cameras.

 

Dear NK Guy,

 

I think you are right, it does look like that adaptor, but mine has to be cheaper than yours was, as it doesn�t have a close-up lens on the back. The lens cap has in big letters "I.R. Beam", so I suppose that is the brand name. When you look into it, from the front, it looks red, if you look through the view finder you don�t see red. �The lens� is a Canon zoom lens EF 35-80mm 1:4-5.6 III. I didn�t think that was something that was pertinent to the screw on lens. I�m sorry.

 

Thank you very much for the information, and the link to your beginner page. I will really enjoy reading it.

 

Sincerely,

Jackie

>The lens cap has in big letters "I.R. Beam", so I suppose that is the brand name. When you look into it, from the front, it looks red, if you look through the view finder you don?t see red.

 

It does sound like some random cheesy no-name brandname, yeah. As for the colour if you don't see a red tint when you look through the viewfinder then it isn't red. Any reds (or greens) you may see when you look at the exterior surface of the lens, particularly off-axis, is probably reflection caused by the lens coating.

 

>?The lens? is a Canon zoom lens EF 35-80mm 1:4-5.6 III. I didn?t think that was something that was pertinent to the screw on lens. I?m sorry.

 

No, you're quite right that in this case it wasn't really relevant at all. I just think it's useful to supply lots of detailed information when asking a question just in case it turns out to be relevant. :)

Kit lenses are usualy very bad in terms of optical quality. Get yourself a Canon 50/1.8. It's cheap, fast and sharp.

Jackie,

 

You're right, there is a lot of info on net about IR but hard to find anything helpful to your question. I did a couple of Google searches without much success.

 

I just saw this site and thought it might lead you to some help, either from its links or by contacting them via email about your filter.

 

http://www.cocam.co.uk/CoCamWS/Infrared/INFRARED.HTM

 

Hope this helps - good luck on your search.

 

Cliff

Dear Cliff,

 

VBG.... I think that has to be it.

 

�An auto focusing camera could be used for IR photography using a very wide lens set at a small aperture. The larger depth of field would compensate for the non-IR focussing of the auto focussing system

 

IR filters are generally opaque so normal use with an SLR means that when the filter is attached to the front of the camera then you cannot see through the viewfinder. Some people only use red Wratten 25 filters which you can see through so that they can still see use the viewfinder normally with the filter attached�

 

The above quote from that site makes it sound like that lens was made to incorporate the extra wide lens with a red Wratten filter.

 

I suppose the next mystery would be why would anyone use an Eos camera to do IR photography. I don�t think I will try to figure that one out.

 

Thank you so much.

 

Jackie

It can be done--but you focus manually when using infrared-sensitive film! AF won't work with an "IR" filter in place.<p>A number of people, e.g. <a href="http://www.a1.nl/phomepag/markerink/mainpage.htm">W.J. Markerink</a>, use EOS gear for IR photography. The Rebel models are hardly useful for this as they use an infrared LED to check film advance, i.e. they fog the the film.<p>In case anyone wonders what the "S7/52" on the device you mentioned, Jackie, means: the version of the oddity I encountered has a Series 7 filter thread and is mounted on the lens via a Series 7 to [your lens's filter thread] mm step-down ring.