what makes macro lenses special?

[florenceinitaly]

so how do you know if the picture is 1:1 or not? It might be like 1:1.5 or something?

 

[Josh66]

so how do you know if the picture is 1:1 or not? It might be like 1:1.5 or something?

It will say on your lens. (If you have a macro lens)

 

[Derrel]

Macro lenses are also known for having excellent flat field correction at close focusing distances. Where a 'regular' field telephoto or a telephoto zoom lens might tend to come to a different point of best focus in the middle and at the edges of the frame, a good macro lens will have a "flat field". A good macro lens will also have very low linear distortion, with no noticeable barrel or pincushion distortion.

Most dedicated macro lenses have a very broad range of focusing adjustment from 1:1 or 1:2 out to longer distances such as 1.5 meters, with a lot of movement of the focusing ring within the close-up range,which allows precise focusing. Most, but not all macro lenses, focus from 1.5 meters to Infinity with a very short,abrupt turning of the focusing ring, which can lead to hair-trigger focusing at distances that are beyond the close-up range.

 

[Overread]

Also something that might have got overlooked. The 1:1 notation on a macro lens is its magnifcation factor. Now if you take a 50mm macro lens and a 200mm macro lens and focus both to 1:1 (ie closeset focusing possible with each lens) because you are focusing to a ratio between the subject and the image sensor on the camera, both lenses will give you the very same framing of the shot.
Which means differing focal lengths mostly only affect your working distance - which is the distance between the lens and the subject (not to be confused with the minimum focusing distance which is from the subject to the sensor in the camera). Of course other differences in lens constrution and features are also present in the choice as well.

Also, generaly speaking, you want a macro lens of at least 90mm in focal length or longer if you intend to take photographs of bugs, since the longer the working distance of these lenses the less chance you have of spooking the insect. This is not ot say shorter lenses cannot be used, they can, but they are a harder setup to master the use of.

 

[Bitter Jeweler]

Thanks Overread! I did not realize that. (100mm/200mm 1:1 yield the same frame).
So if a person whats more magnification, you'd want to go a lens with 2:1.

 

[Overread]

Correct - more magnification will need a lens with a different magnification factor. The current production lines for canon, nikon and most other DSLR manufacturers only make 1:1 capable macro lenses. The only execption to this being the canon MPE65mm macro which goes from 1:1 to 5:1 magnification and is also only capable of taking macro photos (it has no infinity focus).

There are older options which can be used for greater than 1:1 magnification - most of these are fixed magnification options rather than the zoom of the MPE lens. I, however, don't have enough hold on that area to be able to make any recomendations.

Further whilst greater magnifications are possible, once you start to go greater than 2:1 magnification taking shots gets a lot harder - handshake is very hard to deal with in terms of framing, whilst lighting is also more tricky and your focusing distances will be getting very small indeed.

 

[Ron Evers]

I have to jump in here.

I use extension tubes for macro work & the literature says that you achieve 1:1 when the extension tube length equals the focal length of the lens. So, if one uses a 50mm lens & adds 50mm of extension tubes you should get a 1:1 macro. Now here is where it gets complicated, my body has a crop factor of 2.0 meaning a 50mm lens is equivalent to 100mm on a 35mm film camera. Does that 50mm lens + 50mm extension now yield a 2:1 macro? I think so but am not sure.

Here is a macro/micro of bread.

 

[bahandi]

Hi Ron. I, of all people, have no real weight behind this answer because someone else said it to me. Crop factor does not equal magnification (in the same way you crop a picture to 100%, you're not actually magnifying it). So no, you will not be achieving the 2:1 magnification.

 

[Ron Evers]

Hi Ron. I, of all people, have no real weight behind this answer because someone else said it to me. Crop factor does not equal magnification (in the same way you crop a picture to 100%, you're not actually magnifying it). So no, you will not be achieving the 2:1 magnification.

Thanks, that makes perfect sense.

 

[Derrel]

If a person wants more magnification than 1:1, an affordable, easy way is to reverse-mount a short focal length lens on the front of a moderately long lens, like a 200mm lens. A very common pairing is a 200mm with a 20mm wide-angle reversed and threaded to the front of the 200mm lens. All that is needed is an inexpensive filter reversing ring, sold by a vendor like Fotodiox for example.

The aperture of the front lens is left wide-open, so any number of inexpensive lenses can be used for the front or reversed lens. With just "regular" non-macro lenses, it's possible to get 4x to 5x lifesize, high-magnification photos.

 

[mahum]

thank God for this forum, You all explain things so us "newbies" get it the 1st time !!!

 

[Phranquey]

If a person wants more magnification than 1:1, an affordable, easy way is to reverse-mount a short focal length lens on the front of a moderately long lens, like a 200mm lens. A very common pairing is a 200mm with a 20mm wide-angle reversed and threaded to the front of the 200mm lens. All that is needed is an inexpensive filter reversing ring, sold by a vendor like Fotodiox for example.

The aperture of the front lens is left wide-open, so any number of inexpensive lenses can be used for the front or reversed lens. With just "regular" non-macro lenses, it's possible to get 4x to 5x lifesize, high-magnification photos.

I've got a reversal ring, and they are neat, but the DOF is razor thin.

 

[fokker]

If a person wants more magnification than 1:1, an affordable, easy way is to reverse-mount a short focal length lens on the front of a moderately long lens, like a 200mm lens. A very common pairing is a 200mm with a 20mm wide-angle reversed and threaded to the front of the 200mm lens. All that is needed is an inexpensive filter reversing ring, sold by a vendor like Fotodiox for example.

The aperture of the front lens is left wide-open, so any number of inexpensive lenses can be used for the front or reversed lens. With just "regular" non-macro lenses, it's possible to get 4x to 5x lifesize, high-magnification photos.

I've got a reversal ring, and they are neat, but the DOF is razor thin.

It is possible to change the aperture, by fitting it to the camera as usual, stopping down to your chosen aperture, then pressing the DOF preview button and while holding it, turning off the camera then removing the lens.