100mm or 150mm Macro?

Tiziano · May 4, 2009

So I'm really digging shooting flowers with my Sigma 17-70mm Macro. I find however that I'd like a little more DOF and was thinking that a telephoto macro might do it for me as I believe I could put some more distance between me and the object. Is this thinking correct?

Either way, I'm looking at the Sigma 100mm and 150mm Macro offerings (plus the Tokina 100mm). Any suggestions?

Chrissiebeez_NL · May 4, 2009

not sure if this is completely correct but here is my take on it:
In normal lenses the depth of field will be determined by the diafragma chosen (maximum may be limited to F = 4 or something), the focal length (wide angle v.s telephoto and the distance of foreground (focused subject) to background. If the distance between foreground and background is biger, it will be more out of focus creating bokeh, but a longer focal length will also create more smoother background because less is in the frame. macro lenses will not necesarilly put more distance between you and the subject but have a very limited depth of field by their design. Most of the time you will want to try to maximise this instead of the other way around

so yes, a macro lens will reduce the depth of field significantly. A second aspect is the larger diafragma of F = 2.8 which also helps, also when your not doing macro work. longer focal length lenses will have smoother backgrounds as well.

i recently purchased the tamron 90 mm and i noticed very soon that when you want maximum magnification (focussing when close to subject), the barrel extended quite a lot, decreasing the working distance. this may not be a problem when shooting flowers but it was a bit difficult with insects/butterflies. I believe the sigma and canon 100 mm's do not extend to that degree. you can see it here in the MWD table:

http://www.the-digital-picture.com/Reviews/Tamron-90mm-f-2.8-Di-Macro-Lens-Review.aspx

the sigma 105 and 150 mm also have reviews here:

http://www.the-digital-picture.com/Reviews/Sigma-105mm-F-2.8-EX-DG-Macro-Lens-Review.aspx

http://www.the-digital-picture.com/Reviews/Sigma-150mm-f-2.8-EX-DG-HSM-Macro-Lens-Review.aspx

In this effect, the sigma 150 mm seems the best in terms of focal length, working distance and price/image quality but the price is a bit higher than say; the tamron 90 mm.

hope it helps, good luck!

ziggy53 · May 4, 2009

Tiziano wrote:

So I'm really digging shooting flowers with my Sigma 17-70mm Macro. I find however that I'd like a little more DOF and was thinking that a telephoto macro might do it for me as I believe I could put some more distance between me and the object. Is this thinking correct?

Either way, I'm looking at the Sigma 100mm and 150mm Macro offerings (plus the Tokina 105mm). Any suggestions?

I do prefer true macro lenses that are from 90mm and 180mm just because they provide better positioning distance for lights than the shorter focal length macro lenses.

DOF is always very shallow at macro distances and "DOF stacking" is common and our Lord Vetinari is very good at stacking images for DOF using CombineZM.

http://www.dgrin.com/showthread.php?t=61316

It is true that a longer focal length macro lens will have a bit more DOF, but at true macro distances the difference in DOF may not be as much as you think it would be. Take a look at the following link and scroll down to the section marked, "DOF at constant magnification III" (scroll the page down to around 60 percent.)

The difference between the DOF of a 60mm lens at macro distances and a 100mm lens at macro distances is only .21 mm and an increase of around 20 percent. While the increase in DOF is real, it may not be worth the trouble since things like camera shake will magnify by the full factor of the increase in focal length (it's harder to control a longer focal length lens without shake.)

Tiziano · May 4, 2009

Thanks guys!

Photoskipper · May 5, 2009

I use the Canon 100 mm Macro.

It is mainly because the 60 mm Macro cannot fit the 5D, and the 180 mm is too big, heavy (over 1 Kg) and expensive (I could not afford it)

The 100 mm is F2.8 which also good for portrait. It is lighter and I can bring along for field use on top of the 70-200. The 180 mm is F3.5.

The front lens diameter is 58 mm compare to the 180 which is 72 mm. I had a lot of 58 mm UV filter, color filter and most important - the close up filters also. It helps me to save a lot. 58 mm filter is much cheaper than 72 mm.

Awais Yaqub · May 5, 2009

After using 100mm 2.8 USM i highly recommend it ! excellent lens. But now i need a flash to shoot macros at high magnification.
It worked flawlessly with Portraits and Landscape too !

jonboy61 · May 5, 2009

I chose the Sigma 150mm F2.8 Macro for a few reasons. It does have the f2.8 aperture although I don't shoot much macro at that F stop. It has a tripod ring included with the lens. But mostly the focal length allows me to stay farther away from the subject which leaves room for ambient light or flash to get to the subject.

Robinivich · May 5, 2009

jonboy61 wrote:

I chose the Sigma 150mm F2.8 Macro for a few reasons. It does have the f2.8 aperture although I don't shoot much macro at that F stop. It has a tripod ring included with the lens. But mostly the focal length allows me to stay farther away from the subject which leaves room for ambient light or flash to get to the subject.

Couldn't have put it better myself. If you're ready for a little learning curve with regard to stabilizing the lens, having the 150mm's extra reach is very nice for bugs.

paddler4 · May 6, 2009

Check out this explanation: http://www.cambridgeincolour.com/tutorials/depth-of-field.htm. The poster argues that increased focal length has very little effect on DOF, but to the extent it does, it slightly decreases it. What I find really helpful is that the post helps clarify the distinctions among real DOF, magnification, and apparent effects on DOF from the foreshortening of perspective that longer focal lengths bring.

The poster also says that focal length DOES change the fall-off in focus, with short lens giving a more gradual falloff to behind the point of focus.

Tiziano · May 6, 2009

Good link.
I think I'd been there before but it was a good refresher.

Trouble is, I'm still thinking that distance from sensor to focal point is a factor. Hence the ideas of a 100mm or 150mm lens.

catspaw · May 6, 2009

photograham wrote:

Why not get both

I'd get a 60mm and 150mm if I could re-do this. (I've a 60 and 105. too close)

Tiziano · May 7, 2009

photograham wrote:

Why not get both

$:D

My 17mm-70mm Macro seems to handle the short end quite well. The goal was to get farther away and closer at the same time, hence the 100mm or 150mm. As it is I think my Visa account needs a break for a bit just now.

Shizam · May 7, 2009

I've used the Canon 100 and 180L as well as the Sigma 150 back when I liked doing macro and found that while the 180 and 150mm lenses were great to get a long 'working distance' it turned out that was a liability as often as it was a plus. If you're shooting bugs or something such that you know you _need_ a far working distance then the 150 or 180mm lenses are invaluable. However I liked shooting non-bug subjects and having to back up enough to get the shot I wanted was a PITA. I feel like 100mm is a great compromise, any shorter and you're right in the subject's lap, any further and you really gotta backup unless you want 1:1 for everything.

Tiziano · May 8, 2009

Thanks Shizam.
To be honest, bugs creep me out (other than dragon/damselflies).
I'm mostly interested in flowers as I live within 5 miles of the Minnesota Landscape Arboretum.

A shot from a recent jaunt here using the Sigma zoom/macro I have.

100mm or 150mm Macro?

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