Frequently Asked Questions
Q. I have a 100mm macro lens and both a full frame and crop sensor camera. Which camera would be best to bring as the crop sensor makes the lens to an equivalent 140mm?
A. Generally speaking a 1.5X crop camera would make a 100mm macro lens the equivalent crop of 150mm so it would make a better choice with skittish subjects like bees, spiders, etc. Also because of the increased distance the crop body and 100mm would give you a stop and 1/2 more apparent depth of field.
The Sigma 105mm macro lens on a full frame body is a super sharp combination and a my favorite of mine. It's a good balance of size, weight and just enough working distance.
Q. I do not have a dedicated macro lens, what do you recommend for a macro workshop?
A. You do not need a special lens to create wonderful close-up images. A close-up lens or diopter is a great choice to use with an existing telephoto or zoom lens. These would attach to front of lens or with an adapter.
One of my favorites are the Raynox DCR-150 and the DCR-250, +4.8 and +8 diopters. Both of these are sharp, reasonably inexpensive and come with an plastic adapter to fit lenses from 52-67mm, I would recommend upgrading to metal mounting ring eventually as the adapter than break if not handled carefully. These are very high quality optics consisting of 3 elements in 2 groups.
Using the DCR-250 on a 28-135mm zoom would put you right at 1X or life-size at 135mm. The DCR-150 on the same lens would give right over 1/2x half life-size.
Here is a great list of available close-up lenses, for best results always use high quality multicoated and multi-element close-up lenses.
Raynox pros and cons
Very good value for your dollar
Great image quality
No light loss like a teleconvertor or extension tube
Decreased working distance
Plastic adapter should be replaced if you plan to use the lens a lot
Q. Can you please advise which focal length macro lens you recommend?
A. Although I own 50mm, 70mm, 90mm, 105mm, 150mm and 180mm focal length macro lenses, my favorite all around macro lenses are the 105mm and 150mm Sigma macros.
Longer lenses like the 180mm will give you more working distance and better bokeh but they are heavier more expensive. Sometimes the 180mm macros will cause issues with too much working distance.
I would not recommend much shorter than 100mm if you are using a full frame camera since this can create problems with shading and blocking light due the short distance from the subject to the front of the lens.
You should be aware that modern lenses like the sigmas use internal focusing. As these focus closer the length of lens remains the same but the focal length will shorten. A 105mm macro can shorten down to 80mm or so at 1X or life-size magnification. If you add extension to a 105mm enlarging lens to reach the same 1X the lens will not lose any focal length. BTW this should not be confused with the term focus breathing.