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11-21-2011, 02:30 PM   #1
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help with my lens

Hi to all

I'm a total beginner and would like to ask anyone with the knowledge

Wanted to ask I'm interested in macro photography and i have an Manual Sigma Zoom 18mm 200mm macro lens. When going to the store all they seem to want to do is for me to spend more money on a lens and not giving me any alternative ways round it, do you think i could use some extension tube's onto this lens. I'm a complete novice to SLR'S

I've just bought my new Pentax k-5. plus kit. I totally love it.

They have told me that the sigma lens is in great condition but suggested i go and spend another 500 on one of there lenses i don't have that budget at the moment as i have to go in for a major op this Thursday on my back,

Any help would be much appreciated..
Thanks

11-21-2011, 02:50 PM   #2
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Is that this lens? Anyway, stores always want you to buy stuff. What macro subjects do you like shooting? Figure out what magnification you're after, and what working distance (distance from front of lens to subject) is workable for those subjects. Read RioRico's amazing article on cheap macro options. Have a look in the forum marketplace to see if there's a lower-cost dedicated macro lens that would suit you -- you don't really need or even want autofocus for true macro work, so an older manual-focus lens might do the trick.
11-21-2011, 03:07 PM   #3
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Thanks
I would like to take photo's of insects with this lens
if its possible, I was surprised when i went to the store as most of them where professional photographers And didn't give me any suggestions. Do you think the lens i have is a good one it has no scratches or fungus on it at all ( 72m Sigma Zoom 1;4 -56 f=28 - 200mm multi coated lens ) and can i put extension tubes on it ...
11-21-2011, 03:09 PM   #4
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just realized the picture you put on no that is not the lens i will try and put a photo of it if i can.

11-21-2011, 03:38 PM   #5
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hi Baro-nite i managed to upload a photo of my lens to my account but cant fiugure out how to put on this thread but thanks anyway i figure it out somehow.
11-21-2011, 03:47 PM   #6
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If you add extension tubes, you will
1) likely find it extremely hard to focus. Adding extension tubes will make your image in the viewfinder darker, and this is a relatively slow lens.
2) Probably lose the ability to control aperture on the body (still possible on the lens, if it has an aperture ring, just turn it off auto). There are suitable extension tubes, but they're hard to find.

Most zoom lens won't magnify more than your kit zoom lens (18-55) already does. While a larger focal length (200mm vs. 55mm) lens makes things farther away bigger, making close things bigger is another matter. The magnification on your kit zoom is 0.34x, which is already pretty good. IIRC, adding extension tubes to it will be more productive, though there is no aperture ring.

If you want better than it for cheap macro lenses, read the thread already pointed out:
https://www.pentaxforums.com/forums/pentax-lens-articles/152336-cheap-macro-b...lose-work.html

You may be able to use your lens with a reversing ring.
11-21-2011, 04:16 PM   #7
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Still not sure about your exact lens model, but as a superzoom labeled "macro" I'd guess the maximum magnification is around 1:3 or 1:4, a little limited for bug macro. Ideally this calls for high magnification and longer working distance, an expensive combination in a dedicated macro lens . Check out that cheap macro article, and also have a look at the Macro by any means necessary club; some fantastic work there and much of it with low-cost setups.
11-21-2011, 04:35 PM   #8
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Another option is to use this raynox DCR-150 or DCR-250. The link provided is just for the numerous reviews there. (P.S: Well! the links provided above discuss this option as well)

Raynox DCR 150 Converter


Last edited by pcarfan; 11-21-2011 at 04:46 PM.
11-21-2011, 04:44 PM   #9
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Is this the lens?
SIGMA 28-200MM F4-5.6 AUTO FOCUS LENS FOR MINOLTA | eBay
11-21-2011, 04:55 PM   #10
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QuoteOriginally posted by pcarfan Quote
Another option is to use this raynox DCR-150 or DCR-250.
Indeed, and there's one available on the forum marketplace
11-21-2011, 06:23 PM   #11
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QuoteOriginally posted by baro-nite Quote
Indeed, and there's one available on the forum marketplace
I'd recommend the DCR-150 for a long zoom like the 18-200, not the DCR-250. The 150 allows a longer working distance and less extreme macros. It will still get to over 1:1 on a 200mm lens, so it is quite powerful. The 250 is also more likely to vignette than the 150.
11-21-2011, 06:25 PM   #12
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thanks

Thanks for all your support and suggestions, i will keep them in mind, But at this moment i wait till i recovered from my operation and look into it further.
it looks like i will probably go for a better lens to do this kind of work.
there's not to many honest people sometimes at theses stores
but im sure i will find the right lens.
Thanks again to all that has commented..
11-22-2011, 02:11 PM   #13
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Don't bother with the retail shops, most are useless.

There are always good macro lenses available here at the marketplace. Set up a watch for "macro" and even the mm you want like FA100 or just 100mm and you'll see. Plus, then you'll get an idea about how much you'll need to budget to buy one. Don't be afraid of older lenses, particularly for macro - there are some old gems out there.

I really enjoy the FA 100mm macro I bought years ago.

Last edited by TER-OR; 11-22-2011 at 02:11 PM. Reason: adding comment
11-22-2011, 02:34 PM   #14
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QuoteOriginally posted by TER-OR Quote
I really enjoy the FA 100mm macro I bought years ago.
That one used sells for almost the same price as a new D FA 100mm.
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