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Photography Question 
Michèle J. Thomas
BetterPhoto Member Since: 7/17/2004

How do DSLR lenses compare to digital

I have been using the Fuji Finepix s-9000 for a year or so, and before that the fuji Finepix s-7000. This camera takes great super macro shots, which is my first choice on taking photos.
I also shoot nature scenes, birds, in a distance, lake scenes, and architectural shots. My problem is that I never used a 35mm camera, and no nothing about lenses. I've been told that I have a great eye for composition, and am very creative.
I bought the Nikon D80 9 months ago, and only have the one kit lens 18-55mm. When other photographers see my photos, they ask, what lens did I use, and what shutter speed, etc. I'm almost ashamed to say , " I'm still using my Fuji finepix s9000, because I don't know much about lenses, and how they work...etc. I've bought a lot of books on basic photography, DSLRS etc., but they all seem to take for granted that you know about film 35mm, or digital lenses (mm). I'm looking into the Nikon 105mm f/2.8g ED-IF-AF-svr Nikkor (macro lens)(which is real pricey)& the Nikon 70-300mm f/4.5-5.6GED-AF SVR zoom lens. I want a 12-15 optical zoom and don't know how that translates into a digital mm lens. Also wonder if that macro will get me as close as my Fuji super macro, which lets me capture subjects as close as a 1/2 inch away. Also, does anyone have advice on whether you should purchase lenses locally, and purchase the replacement plan, etc., or if you're better off purchasing from a reputable on line photo company, with much lower prices and free shipping and no tax, and just the regular Nikon warranty that automatically comes with the lens?
I'm really not stupid, even though it may appear that I am. I guess since I have a good eye for photography, and love it, and people like my photos.... I need to move on instead of mostly using my macro or auto setting on my FUJI. I have won several competitions, and have some of my photos for sale at a local Gallery. I just feel like, oh-oh, I don't want them to know I'm using the Fuji, with one lens, and mostly on automatic. (Also, if I purchase those lenses, I probably won't know how to use them, properly.

I would appreciate any advice on this, and thank you ahead of time, for any responses.



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8/28/2007 2:12:51 PM

Jason R. Fortenbacher
BetterPhoto Member Since: 9/11/2006
  It can be very overwhelming going from a digital camera to a DSLR. The one piece of advice I can tell you is just what others told me when I was in your exact same position: GO OUT AND SHOOT! :) Take the DSLR with its new lens and fire away. Make sure you're not photographing something where you will be devistated if the picture turns out bad, but try all the different settings and modes. Go back to your computer and then look at what the EXIF data says and compare results that way.

It can be as simple as putting the camera in Shutter Priority (Tv) and take successive pictures at slower (or faster, whichever way you want to go) speeds. Then go to Aperture Priority (Av) mode and do the same.

Pay attention to how setting your aperture affects your shutter speed and vise verse.

When you're all done with that try putting the camera in full manual and then change both the aperture and shutter manually and see how they relate. (ie. fast shutter + narrow aperture = underexposed)

Good luck and most of all, don't give up. Just bust out that nice DSLR you have and give it a whirl!

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8/28/2007 3:36:57 PM

Bob Fately   Michele, I will try to help, at least a little...

First, on the lens issue: the important measure of a lens is its "angle of view" - that is, from the focal point in the lens (where the light beams "cross over", if you can think of the simple optical schematics from high school), how wide is the view the lens 'sees" and then projects back onto the film or digital chip.

The focal length (the MM measurement) determines the angle of view; again, thinking of that simple schematic, the distance from the "crossover point" to the film or chip is the focal length. Thus, the angle of view for a given focal length depends entirely on the size of the film or chip being exposed.

Since 35MM cameras were so overwhelmingly popular, the industry at large has settled on the focal lengths used in that world. So in that paradigm, a 50MM lens is "normal" (giving about the same angle of view as human perception, around 46 degrees). Longer than 50MM is telephoto, shorter is wide angle.

With most digital cameras, the size of the chip is smaller than the 24x36MM frame size of a 35MM camera. [aside: this is not always true, Canon and now Nikon have so-called "full frame" DSLRs, and a bunch of companies offer digital backs for medium format bodies with chips that are 36x48MM in size - but they cost $29K+]. Anyway, to get the same angle of view on a smaller imager size, you need a shorter focal length. This is usually expressed as the "crop factor" (because it's the same as if you took the full 35MM negative and just used the central portion, cropping out the rest).

If the DSLR crop factor is 1.5, this implies that you can expect a 50MM lens on that camera to give you about the same angle of view as a 75MM lens would (1.5 x 50) on a film 35MM camera.

Now, on the macro front, the important thing is the comparison of the size of the actual subject compared to the projected size on the chip inside the camera. If you take a photo of a stamp that's 1/2" square, then if you can get close enough with the lens to get a 1/2" image on the chip (or film) you are in the land of macro. WHile my example is a 1:1 ratio, macro generally is considered anything that get's to half-life size or larger.

As you can imagine, to do macro means the lens needs to be able to get close to the subject. Macro lenses made for the purpose are generaly sharper than "all purpose" lenses that can focus close. However, exactly how close depends on the focal length of the lens. So, with a 50MM lens you might need to be 6" from that stamp, with a 200MM macro lens you can be perhaps 20" from that same stamp and get the same image on the CCD. But at 20" away, you have more room for lighting, or distance from you and that skittish bug or snake you're shooting. The point is, it's not all about getting to 1/2 inch away - it's about sharpness of image and "working distance".

Obviously there are many more details, but hopefully this gives you a start. As for using local versus mail-order - as long as you deal with a reputable dealer either way you should be okwy. However, having a local store to give you hep (like this) and hands-on experimentation is usually quite worth the higher price. Sure, you could spend 3 hours at the local store and buy online, but that's a matter of your ethics.

Hope that helps...

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8/28/2007 3:45:29 PM

Michèle J. Thomas
BetterPhoto Member Since: 7/17/2004
Thank you, Jason and Bob, for your responses. You've given me some really good info, and I appreciate that very much. I'll be taking both of your advice, asap.


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8/28/2007 5:24:39 PM

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