is a 10-20mm lens and a 15mm fish eye lens similar?

[sean_mcr]

One of the main reasons why you would use an slr is because you want the right tools for the right job.

You have to sit down and think long and hard about what you want to do. Then you need to find out what will allow you to do that. There is no one size fits all answer.


The fisheye is no more of a Macro lens then a macro is a fisheye. They are two different lenses for two very differnt tasks

[djwixx]

I was reading the Canon 15mm e/f fisheye lens and it mentioned that close focus was at 0.7 ft......does that not give you real close-up shot of stll life 1:1 sharply? or do you still need an extra add on to get clost up shots sharp?

Boy , I am starting to learn fr everyone. thnx guys

15mm may be close focusing but it's wide, so you may be 8" away from an object but your field of view will be over a foot wide. A macro lens will get you the same focul distance but your field of view will be several inches. Look at what your 18-50 gives you at both ends - that's the difference.

[ignorant88]

thnx everyone esp sean_mcr and dong for the help. I did not see there was a 2nd pg response and thus posted sometyhing similar elsewhere. sorry.

since cropping came up....any problem with taking a wider view an then crop the pic? will it affect qlty of pic or is it just a matter of perfection that one should not crop their pic?

[andrzejmakal]

croping is nice technique, but better avoid it and buy macro lens. Try to crop 1/10 of the frame, then print it in large format, say 20/30 cm and you`ll see...
Regards

[thelund]

since cropping came up....any problem with taking a wider view an then crop the pic? will it affect qlty of pic or is it just a matter of perfection that one should not crop their pic?

Cropping a wide-angle image to get close up of a small object will cost you lots of pixels, so you will be left with a low-resolution image!

The Tamron 90mm f/2.8 macro is VERY sharp, recommended by most macro photographers I know. I have the Sigma 105mm f/2.8 myself though, and I am very happy with what it delivers.

Focal distance (?? mm) does not tell you anything about how close you can get, the maximum magnification does that! The focal length tells you something about the field of view you will get with the lens, exactly how i will not bother explaining unless you are good at maths! - But shorter focal length is wider FOV.

Sigma have all their info publicly available, for example for the 105mm macro max. magnification is 1:1, for the 10-20mm it is 1:6.7 - Info is in the lower right side of the page:
http://sigmaphoto.com/lenses/lenses_all ... avigator=5
http://sigmaphoto.com/lenses/lenses_all ... avigator=6

A magnification of 1:1 means that you can have an object the same size as the sensor fill the whole image at closest focus. A magnification of 1:6.7 means you can have an object 6.7 times larger than your sensor fill the image at closest focus!

A fullframe sensor is 24*36mm (approx 1*1½ inch), so at closest range a 1:1 macro will get you so close that most butterflies will be too big to fit into the image!
On my 350D a bee takes up a good deal of the image at closes focusing distance.


Brian