On DX lens

[chatswood]

Just a little question on DX lens with use on DSLR. Does the 1.5 mag factor applies? Meaning 18-70mm becomes 27-105mm on a D70 body?

[espn]

Yes, it still does.

[Hobbes234]

Originally Posted by chatswood Just a little question on DX lens with use on DSLR. Does the 1.5 mag factor applies? Meaning 18-70mm becomes 27-105mm on a D70 body?

please note that the 1.5 factor does not mean any increase in object magnification.
It will be the same magnification as a full frame DSLR/SLR, its juz that your image, when viewed, will be only cropped by that factor.
(i.e. you have a lesser viewing angle).

[bonfire]

Originally Posted by Hobbes234 please note that the 1.5 factor does not mean any increase in object magnification. It will be the same magnification as a full frame DSLR/SLR, its juz that your image, when viewed, will be only cropped by that factor. (i.e. you have a lesser viewing angle).

Sounds very technical. To put it in an easier way, you get extra zoom range.

[espn]

Originally Posted by bonfire Sounds very technical. To put it in an easier way, you get extra zoom range.

Urm, nope. You do not get extra zoom. You get a cropped image instead.

[LeeDan]

Originally Posted by espn Urm, nope. You do not get extra zoom. You get a cropped image instead.

Can explain more with example, don't quite understand？

[ortega]

take a 4r picture and cut off the 4 sides
Crop factor, get it?

[Jed]

And, this is not being condescending, but what's the difference between more magnification and a crop?

[ParkertR]

hmm... Jed has a point. when you do a crop, you're basically 'magnifying' the image by cropping it closer to the subject... am i right? or wrong...?

[user111]

crop may imply loss of image quality

but

magnification via optical zoom usually doesnt imply loss of image quality

but all this is still playing with words..hehe

[fuzzy]

try cropping a picture taken with a 50mm lens by 1.5x and compare it with a picture taken at 75mm... there will be subtle differences... (other then bokeh, and pic quality)

[Jed]

Originally Posted by user111 crop may imply loss of image quality but magnification via optical zoom usually doesnt imply loss of image quality

This is largely a side issue when discussing DX sensors, since the full frame isn't available to begin with, so you can only get as much quality as your cropped image to start with.

[Jed]

Originally Posted by fuzzy try cropping a picture taken with a 50mm lens by 1.5x and compare it with a picture taken at 75mm... there will be subtle differences... (other then bokeh, and pic quality)

I didn't ask if there would be differences or not. I asked, what's the difference between magnification and a crop? Which I still don't get.

Come to think of it, with reference to what you suggested, I'm not even sure there will be differences with a 50 x 1.5 or a 75, bokeh aside.