New venture into Macro
 

I want to expand my interests into Macro photograpy. Up to now I have used my CP4500 or my 300D with a Sigma 50-500 for small subjects.

My questions are

1.What are the advantages of a dedicated macro lens?

2.Also I don't understand the magnification ratios quoted in the tech specs for macro lenses.

3.Can a macro lens of say 150mm be used for general photography?

Can anybody suggest a suitable lens? My budget is c£300. Possibly either Canon/Sigma/Tamron

Ken,

1. Strictly speaking, in film terms a macro lens is: A lens capable of giving a 1:1 or greater magnification ratio of subject to image on the film. How this definition translates to digital sensor image size I'm not sure, I'd imagine it to be the same. The term is more generally used to describe any close focusing lens.

2. Magnification ratios, see point 1, it's a measure of how big the actual subject is vs. how big the image on the film/sensor.

3. Macro lenses can be used for "normal" photography.

I'm not sure exactly what you're after when you say "Can anybody suggest a suitable lens" as a lot depends on the subject matter you're taking but I've seen some great results from the Tamron 90mm DI Macro.

Regards,

Duncan.

Hi Ken

Macro lens are tuned to be very sharp at the short end of the focus range and have a short minimum focus distance (MFD).

1:1 is life size and refers to the 35mm format. The idea is that the object will be life size on the film. e.g a 1mm ant will be 1 mm on film.
1:4 will be quarter life size. Don't forget the 300D has a 1.6 crop factor which makes the end result a bit confusing.

Marco lens tend not to focus to infinity very well. In some cases a lens element moves if a lens has a macro switch.

A thing to consider with macro work is that the lens is close to your subject and getting light on the subject becomes a problem.
So you may need to consider longer focal length lens to help with this.

Rob

Personally I use the Sigma 105 f2.8 for macro and am very pleased with it, I've also used the Sigma 50 macro which is equally good. The biggest plus of the longer focal length is that you don't need to get quite so close to the subject.

As others have said a macro lens can be used for other work, but may not do so well at range. Both the Sigma macro lenses that I've used have been great for doing portraits with.

A few points not covered by the others:

The various focal lengths of macro lenses provide for 2 things - a larger image OR more working distance. With some subjects it is difficult (living things) or dangerous (an arc welder) to get close to them.

I use a Canon 100mm macro lens and at times add a 2x teleconverter to it (giving me 200mm and 2x the working distance).

I've also used the 100mm macro with a 3x teleconverter - some results can be seen here: http://www.jbs-blog.com/?p=72

Macro lenses will focus out to infinity and can be used as general purpose lenses but the auto-focus in a macro lens is typically not too good (slow). Since most macro photography is done with a tripod and manual focus, I guess the lens makers just decided to not spend much time on it.

The image at, say, 1:1 will be the same size on either film or sensor no matter what format is in use. Of course, you can't 'see' the image on the sensor to measure as you can with a negative/slide.

A 35mm frame is 36mm wide whereas the sensor on the Canon 300D is 22.5mm wide therefore something of, say, 30mm width photographed at the 1:1 setting will fit nicely on the film but have a bit cut off from each end on the sensor! The most popular (live) subjects in macro tend to be butterflies and dragonflies, etc., and in practice you won't use the very closest settings very often.

Very occasionally you'll get a co-operative damselfly (they're usually very flighty!) and in these instances you can go in very close with a shorter-length macro lens onto something which is about the size of a matchstick! Otherwise, the longer focal lengths give you the dramatic close-ups from a bit further away. However, there's not that much difference in distance from subject to front of lens when comparing different groups of focal length with the nearest group, i.e 50/60mm v 90/105mm v 150mm v 180/200mm.

There's no doubt that the 90/105mm lenses from makers such as Sigma and Tamron are very popular because of the quality available at a reasonable price and whether you want to pay more for the camera makers' own offerings is up to the individual to decide.

Although macro lenses may prove better at the closest distances on the test bench, they're usually good enough over the whole range for most purposes - these two shots, for instance, were taken with a Sigma 50mm macro lens: http://www.worldphotographyforum.com...=500&ppuser=43 and http://www.worldphotographyforum.com...=500&ppuser=43

A bit of overlap there - I was composing my reply when others were being posted!

This is at the other end of the scale with the same 50mm lens (on a 20D), although still not quite at the full 1:1 closest distance. I wonder whether the fact that I was shooting into the light and thus on the 'dark' side of the insect was the reason I was able to get so close to this Blue-tailed Damselfly - they're usually the most wary of the commoner British 'blue' damsels.

It does show the versatility of the modern macro lenses, though - just a twist of the focus ring from one end to the other. No messing about with close-up filters, extension tubes, etc.

Thanks very much for your helpful replies. Everything is clearer now ..... just got to research the best lens choice!

Hi Ken,

The 3 lenses Ive shortlisted for some serious macro work are the Canon 100mm f2.8 macro, the Tamron 90mm DI macro and the Sigma 180mm F3.5 EX DG Macro. Ive read some great reports on each, my gut feeling is I'll opt for the Canon 100mm, as its excellent quality for portraits. These will be some time down the line, im sure.