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06-09-2013, 11:54 AM   #1

Wanting to extend zoom capability

I have bought myself a K-X, and this lens 'SIGMA AF 28-200MM F/3.5-5.6 Aspherical IF Lens' to go with it. I am completely new to dslr's so technical talk is lost on me at present. I read on the Amazon reviews that because of the sensor of the K-X (something about it being 1.5 larger?), a lens can potentially have its zoom multiplied by 1.5? My main reason for having this camera and lens combo is for wildlife photography, and to be able to get closer photos of butterflies and moths with scaring them off so I don't want to stand too close. I am finding that even with this lens, I am still having to get fairly close and they're flying off. I am still not able to get any full-frame photos of insects. Ideally, I'd like the 18-250 Sigma but money will not allow at the moment, not even second-hand. I did try and read up and figure this out on my own but I honestly don't understand the lingo yet. I started to read something about the aperture ring on the lens which I did adjust but it made no difference to me being allowed to adjust the focal length on the camera - now I'm totally lost. Please, could someone tell me if I am able to get more out of this lens on my camera? eg. more zoom? by adjusting something? And, if so, could someone talk it through with me. I do want to learn to use the camera properly but in the meantime don't want to miss any more good photo opportunities. Many Thanks, Sarah

06-09-2013, 12:38 PM   #2
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QuoteOriginally posted by First Poster Quote
Please, could someone tell me if I am able to get more out of this lens on my camera? eg. more zoom
You don't actually get more zoom; what you see through the viewfinder is what you get. The 1.5x crop factor is relative to what the same lens would see on a film camera. Since Pentax's digital sensors have a smaller area than the film frame had in the old days, your K-x sees less of the frame and thus a 200mm would be equivalent in terms of field of view to a 300mm on film (200 x 1.5). In other words, you don't need to have as long of a lens to get tele shots.

BTW, if you want more reach on your K-x, I'd recommend this lens:
Pentax SMCP-DA 55-300mm f/4-5.8 ED Autofocus Lens 21720 B&H

It'll get you much better image quality than those superzoom lenses.

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06-11-2013, 06:11 PM   #3
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The Big Picture?

Hello Sarah-Rose, Welcome to the Forum!
There are three ways to end up with a larger image in a photograph;
Get closer to the subject.
Get a longer lens (for example, as Adam suggested, a 300mm instead of a 200mm).
Take the photo from your present distance, with your present lens, then blow the image up (crop the frame).

Of the three, most close-up (in photography, this is called 'Macro') images are taken with a lens shorter than your 200, in fact 100mm is the most common Macro focal length. Yes, the photographer gets THAT close! It takes patience, skill and with certain creatures, nerve.You should find a likely spot, set up your gear as quietly and unobtrusively as possible and...wait. That's it, there are no great secrets or bizarre techniques, patience and skill mostly. A little luck doesn't hurt!
This applies to tiny or small creatures.
For big critters, Elk, Moose, Buffalo, etc,then a longer (300mm-500mm) lens would be safer, both for you and the animal.
One hint that will help your images, regardless of the distance, size or lens, is to shoot in RAW, stop down slightly (with your lens I'd suggest f/8.0), and shoot at the lowest ISO possible. Depending on the lighting conditions, your shutter speed ideally would be 1/250-1/350s. All of these variables are adjustable on the camera controls, they are 'choices' you make, dependent on (again) the amount of daylight available. The result of these changes is that you will be taking the sharpest photos possible with your gear, the highest resolution and best image quality (I.Q.), therefore the photos can be enlarged to a higher ratio and still be sharp and clear.
I'd suggest looking into a short 'Intro to Photography' course or online tutorials until you are familiar with the basics of ISO, Aperture and Shutter Speed..
Good luck!

Last edited by rbefly; 06-11-2013 at 08:41 PM.

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