Macro Lenses, whats the difference

[Yv]

ok, dimbo question time again.

Macro lenses seem to come in a range of lengths, 50mm, 70mm, 105mm, etc, but what is the difference? Many seem to say they have 1:1 ratio, so I am probably being totally dim, but what would be the pros and cons of say a 50mm over 105mm, and vice versa? Are they purely macro lenses, or does the varying lengths offer degrees of flexibility on less close up stuff? :shrug:

Forgive me if this is a really stupid question, but I feel my education in the art of lenses has skipped something and it's bugging me

 

[Janice]

They still act as a primary lens of the length stated...so a 90mm will act as a good portrait lens too for instance.
They can focus up to get a 1:1 ratio for macro work though.

The longer the focal length the further the distance you can be and still get the insect/flower in the frame at 1:1


This is what I need as I use a 50mm lens with a clip on duberry on the front which means when i approach a butterfly i have to be about 2" away and they fly away every time!

 

[CT]

Most macro lenses are capable of 1:1 reproduction (life sized image on the sensor) while some exceed 1:1.

The main advantage of a longer focal length macro is that they have a greater minimum focusing distance so they give you a lot more distance between your subjects and the lens, particularly important when it's bugs and tiny insects, as there's less chance of scaring them off when you're working from a greater distance.

That greater working distance also means you have less trouble working in your own light and possibly casting shadows on the subject which is a problem at times. It also gives you a lot more room to set up any flash or other lighting arrangements between lens and subject if you need to.

Macro lenses are usually also excellent performers over their whole focusing range as a 'normal lens' of that focal length. My 180 macro is also a pin sharp tele lens.

I think I'd advise 100mm focal length or more if possible.

 

[Yv]

Thankyou guys, thats much clearer.

So the fact that I have been advised to get a 105 sigma as and when the time comes is good!!

 

[CT]

The Sigma is a great lens with a good reputation.

 

[Yv]

Its on the 'wanted' list. Hopefully later this year the two lenses I want to complete my kit [this and a wide angle] will be added to the collection, but I was scratching my head over what different length macro lenses actually meant, so once again, thanks guys.