Tech / Special Interest → Digital Imaging Technology > [Lens] Diopter/close-up filter questions

[Lens] Diopter/close-up filter questions

Hey guys,

Ok, I'm confused here. I got a +1, +2 and +4 set for my 14-45mm lens and am getting some great shots so I ordered a set for my 14-140mm lens, but they're unusable on the 14-140mm and I don't understand why.

On the 14-45mm lens the +4 can focus at about 3 feet and I'm about here in the focal scale: T_________________x______M.

On the 14-140mm though, I can't get the +4 to focus anywhere. No luck with the +2 either but the +1 is all right.

Logic says that since both lenses cover the 14-45mm range, both +4 diopters would work the same on both lenses at least in that range so I'm really confused as to why they won't.

Any pearls of wisdom?
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"While you can teach an old dog new tricks, you simply can't teach him to be a cat."

"Are you my Mummy?"

How close are you to the subject? Try it backwards. Set the focal length, set the focus to about 5 feet, then move the entire camera closer to the subject and see if there's a distance that's in focus.
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***ATMFAQ***DIFAQ***Kitchen Sink***

I've tried it at 3", 10', 60' and 'a building down the block', I couldn't get anything with the +4 and 14-140mm while the 14-140mm alone was better. The +4 14-45mm worked fine. I just don't get it.
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"While you can teach an old dog new tricks, you simply can't teach him to be a cat."

"Are you my Mummy?"

I think you'll need to be far closer than 3'. A +4 on a 100mm focal length has a focus in the range of 8.5" from the end of the lens.
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***ATMFAQ***DIFAQ***Kitchen Sink***

Remember, too, you get a lot less depth of field using diopters.

That's three inches, not feet I've even tried it along a picket fence trying to find the sweet spot but there just isn't one.
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"While you can teach an old dog new tricks, you simply can't teach him to be a cat."

"Are you my Mummy?"

said by Tex:

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Remember, too, you get a lot less depth of field using diopters.

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Try duplicating what I tried. Set the focal length to 100, put the focus at the midpoint, and then look at a ruler from an angle, from less than a foot away. See if any part is in focus.
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***ATMFAQ***DIFAQ***Kitchen Sink***

I think I've figured out the problem - I can't manual focus but I can get them to work with autofocus.

Thanks
--
"While you can teach an old dog new tricks, you simply can't teach him to be a cat."

"Are you my Mummy?"