lens compatibility

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jclark - 06 Apr 2006 20:10 GMT

Hi,

I have have a 52mm close up lense for a canon EOS film 650. I was
wondering if I could also use it on my digital powershot A75? The
powershot A75 says it takes a 52mm close up lense (250D) if I buy an
adaptor. The adaptor is very cheap but the custom close up lense is
about £60, so it would be handy if I could use the one I already have.

Thanks,

Jen

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Paul Furman - 06 Apr 2006 20:18 GMT

> Hi,
>
[quoted text clipped - 3 lines]
> adaptor. The adaptor is very cheap but the custom close up lense is
> about £60, so it would be handy if I could use the one I already have.

Hold it in front & try, it should work but may not be optimized for that
focal length so it's possible it won't look real good. I tried my +2
diopter on a P&S and it didn't seem to have much increase in
magnification so you might check if they use a larger diopter strength
on the official one.

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Tony Polson - 07 Apr 2006 11:27 GMT

>Hold it in front & try, it should work but may not be optimized for that
>focal length so it's possible it won't look real good.

A diopter ("close-up lens") is a diopter is a diopter. It isn't
"optimised" for any particular lens or any particular focal length. It
is just a diopter. It can be used on any lens with the same filter
size.

The OP stated that the close-up lens has a 52mm thread. It will
therefore fit, and work with, any lens that has a 52mm filter thread.
It will also work with any lens with a filter thread smaller than 52mm
but a step-up ring will be needed.

A diopter (close-up lens) works best when the lens it is attached to
is stopped well down, f/8, f/11, f/16 etc.. Diopters work far less
well when the lens is used wide open.

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Paul Furman - 07 Apr 2006 17:50 GMT

>>Hold it in front & try, it should work but may not be optimized for that
>>focal length so it's possible it won't look real good.
[quoted text clipped - 3 lines]
> is just a diopter. It can be used on any lens with the same filter
> size.

My 77mm +2 diopter 500D is specified for use with longer focal lengths,
I forget, like 100-200mm. I assume this has to do with optimising edge
sharpness & such.

> The OP stated that the close-up lens has a 52mm thread. It will
> therefore fit, and work with, any lens that has a 52mm filter thread.
> It will also work with any lens with a filter thread smaller than 52mm
> but a step-up ring will be needed.

I was looking into this last night, it seems the P&S digitals require a
larger diopter rating, more like +7 which bears out my test of the +2 on
a P&S not doing much.

> A diopter (close-up lens) works best when the lens it is attached to
> is stopped well down, f/8, f/11, f/16 etc.. Diopters work far less
> well when the lens is used wide open.

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default - 07 Apr 2006 03:08 GMT

I think it will work fine. The 250D is a +4 diopter dual element acromat
which is very good quality (and expensive) however, ordinary 52mm diopter
filters should work fine too. The 250D works on film and digital SLR's also
that have 52mm filter threads. I think they also make a 58mm version and a
500D which is a +2 diopter.

It will let you focus to a closer distance. diopter = 1/focal length in
meters. So a +2 diopter will move your infinity focus to 500mm etc. This
should allow you larger magnifications since you now have a shorter minimum
focus distance.

Hi,

I have have a 52mm close up lense for a canon EOS film 650. I was
wondering if I could also use it on my digital powershot A75? The
powershot A75 says it takes a 52mm close up lense (250D) if I buy an
adaptor. The adaptor is very cheap but the custom close up lense is
about £60, so it would be handy if I could use the one I already have.

Thanks,

Jen

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