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09-08-2010, 07:33 PM   #1
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Tamron 70-300 or Cosina 100mm for macro?

I've been wondering about macro lenses lately.

I have the Tamron 70-300mm f/4-5.6 1:2 macro lens. I also have a few achromatic close-up filters: Nikon 4T, Raynox DCR-150, Olympus B-Macro, etc.

But I've often wondered about getting a "true" macro lens, for these reasons:

1. Maybe it's me, but I never seemed to be able to get things very "big" when using the the Tamron 70-300. I've had more luck with the close-up filters, using a variety of zoom lenses (Tokina 80-400, Pentax 55-300, etc.)

2. The down side of the close-up filters, though, is the working distance. Different diopters give you different lens-to-subject distances, but you have to swap them out or add on to get much variance in the lens-to-subject working distance.

It seems like a "dedicated" macro lens might do a better job.

Of course, I'm pretty cheap, so I'd be looking for a Cosina-type 105mm f/3.5 lens.

BUT...I have read that particular lens is actually only a 1:2 as well, and requires an add-on filter to achieve true 1:1

So what I'm wondering is:

1. If the Cosina w/o the add-on is 1:2, is it any better than the 70-300?
2. With the add-on filter for the Cosina, do you get the same working-distance issues/limitation that you do with diopter-based add-on filters?

Thanks for any help in this!

Greg

Edit: I changed the title from "105mm" to 100mm. I had the Focal length wrong.


Last edited by gkreth; 09-09-2010 at 06:04 AM.
09-08-2010, 08:29 PM   #2
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Macro ain't macro unless it's 1:1.

I say save your shekels until you can afford either a 50mm macro or a 100mm macro, preferably 100.

A 100 macro gives you good distance from the subject (especially on APS-C sensors) so you can get good bokeh, and it's 1:1. So it's true macro. Plus, they're generally exceptionally sharp and make excellent portait lenses when not necessary for macro work. I would love to have a 100mm macro.

Outside of that, any good lens of say 85mm or more with an extension tube will work as well. That's what I do in the interim, I have one of the Vivitar Series 1 85mm 1.4 manual focus lenses with an extension tube. It's kind of kludgy, and doesn't work well for moving subjects (like bugs or other animals), but is great for still objects that lend themselves to macro work.
09-09-2010, 06:03 AM   #3
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QuoteOriginally posted by brofkand Quote
A 100 macro gives you good distance from the subject (especially on APS-C sensors) so you can get good bokeh, and it's 1:1. So it's true macro. Plus, they're generally exceptionally sharp and make excellent portrait lenses when not necessary for macro work. I would love to have a 100mm macro.

Outside of that, any good lens of say 85mm or more with an extension tube will work as well. That's what I do in the interim, I have one of the Vivitar Series 1 85mm 1.4 manual focus lenses with an extension tube. It's kind of kludgy, and doesn't work well for moving subjects (like bugs or other animals), but is great for still objects that lend themselves to macro work.
Thanks for the reply!

What is the working distance of a 100mm macro lens? Is it literally 100mm, the focal length of the lens?

About extension tubes: I tried to do some research into these, but it seems like the generic ones don't allow for any aperture coupling; i.e., I'd have to shoot wide open. Since I'm more interested in bug macros (as opposed to say, flowers), I'd like to use a lot more DOF, so I expect to be shooting at f/11 or f/16 (with a diffused flash, of course).

From what I've read, I'd have to: 1) focus wide open, then 2) stop down and take the shot. Is that what most do?

Thanks again,

Greg
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