Macro inquiry.

[lordmint]

Dear macro experts,

I have 2 questions that i appreciate to be answered.

1. What would be the difference between the 90mm 1:1 and the 180mm 1:1 other than better working distance and better DOF?

2. In order to have bigger magnification, say, 2:1 upwards, would it be better to to use extension tubes or magnification filters (eg. Raynox) - In terms of DOF, working distance, ease of use.

3. What kind of macro ring flash suitable for my SP90? Do i use canon's or does tamron produce any? If so, how much is the price range?

Thank you =)

[orionmystery]

Hehe..not expert..does that mean I can't answer your questions? BTW, that's 3 questions..not two :)

1. What would be the difference between the 90mm 1:1 and the 180mm 1:1 other than better working distance and better DOF?

>>Besides working distance, i think nothing else. DOF is the same when it comes to closeup. You can read on Wikipedia, the Close UP Section. (http://en.wikipedia.org/wiki/Depth_of_field)

Excerp from wiki: for a given magnification, DOF is independent of focal length. Stated otherwise, for the same subject magnification, all focal lengths give approximately the same DOF. This statement is true only when the subject distance is small in comparison with the hyperfocal distance....

2. In order to have bigger magnification, say, 2:1 upwards, would it be better to to use extension tubes or magnification filters (eg. Raynox) - In terms of DOF, working distance, ease of use.

>>I prefer raynox as it can be snapped on and off easily. Working distance? Don't know..can someone pls answer this? I'd like to know too :)

3. What kind of macro ring flash suitable for my SP90? Do i use canon's or does tamron produce any? If so, how much is the price range?

>>>Hehe..try MT 24EX (http://www.ephotozine.com/article/Canon-MT-24EX-macro-flash). Not sure can mount on tamron or not..