Zoom Frustration

fatsheep

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Today I was walking down my street and noticed an interesting statue someone had in their yard. It was next to their house, about 10 m (~33 ft) away from the edge of the lawn. I didn't want to walk all over their front yard to get the shot so I zoomed in all the way on my camera, standing on the edge of their lawn. I've got a 6.33- 3.3mm lens on my P&S which is equivalent to a 38-380mm on a 35 mm camera.

This seems like a lot of reach. However, despite my relatively close distance, I couldn't come close to filling the frame with the statue (which is about 3-4 ft tall so it's not tiny).

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For a DSLR, 380 mm is quite a long telephoto. It seems like it would have more reach than this? Is there something I am missing?

Also, would a 380 mm on a 35 mm camera really have the exact same amount of magnification as my 63.3 mm lens?
 

Mav

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35mm equivalent focal length refers to the full 35mm film frame. All of the non-pro DSLRs typically have 1.5x/1.6x crop factors which give you a bit of extra reach. If you put a 70-300mm telephoto zoom on one of these you'll get an effective focal length of 450/480mm, and a lot better image quality than a point & shoot zoomed out that far.
 

Gawonii

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I'm just taking a stab at this but think about crop factor for a minute. You see on this forum all kinds of questions about the effects of crop factor on dSLR's and how they change the focal length of lenses. The same thing is happening with your camera but in affect, in the opposite direction. A point and shoot has a much smaller sensor than a dSLR so it takes the focal length in the opposite direction.
Maybe I didn't explain it well but I think you can understand. If I'm wrong, everyone will get a good laugh.
 

Mav

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The focal length never changes on lenses - just the effective angle of view. The P&S has a crop factor of 6.0x. A Canon DSLR has a 1.6x crop factor, which is why you need a much longer focal length to get the same angle of view as a 36.6mm on a point and shoot. All you need to do is search this forum for crop factor - there's one a few threads down - or search on Google for "crop factor" and you'll find all you need to know.
 
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fatsheep

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I understand crop factor. I was just expecting more reach from a lens that has the equivalent magnification of a 380 mm on a 35 mm camera (or ~240mm equivalent for a 1.6x crop factor). For example, if I get close enough in my chair so that I can tough the door nob with my foot and zoom in on it all the way, I can fill just about all of the frame with the door nob. I was expecting the zoom to be able to fill the frame with something the size of a door nob from much farther away than ~3 ft.
 

RyanLilly

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I think that this is one thing that many people have trouble adjusting to when switching from P&S to SLR. P&S sensors are so small they inherently have very long lens equiv. and many are "super zooms." It just takes time for people to train their legs to do the zooming instead of their finger.
 

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