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07-01-2009, 08:32 PM   #1
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50mm Macro vs. 100mm Macro

This may be a stupid question but what would be the difference between these two lenses? I know the f-stop is the same for both. Does one lens allow you to get closer to the object over the other.
I'm trying to figure what the advantage would be to have one over the other or should one have both lenses for macro shots?

Thanks,
Kevin

07-01-2009, 08:59 PM   #2
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The 50mm, being a shorter focal length, will force you to get closer to your subject in order to achieve the same magnification as the 100mm. In this respect it it no different from ordinary (non-macro) 50mm and 100mm lenses.
07-01-2009, 09:05 PM   #3
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Mark,

Thank you, that answers the question and that's what I thought and couldn't really figure out why someone would need both.


QuoteOriginally posted by Marc Sabatella Quote
The 50mm, being a shorter focal length, will force you to get closer to your subject in order to achieve the same magnification as the 100mm. In this respect it it no different from ordinary (non-macro) 50mm and 100mm lenses.
07-01-2009, 09:31 PM   #4
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QuoteOriginally posted by stl09 Quote
Mark,

Thank you, that answers the question and that's what I thought and couldn't really figure out why someone would need both.
The 50mm would be of more use for someone photographing inanimate objects - stamps, jewelry, etc. The depth of field is roughly double at the same magnification and aperture, and the perspective is different as well.

The 100mm is a better choice for taking pictures of creepy crawly things that fly away when you get too close.

The FA* 200mm f/4 Macro would be even better, but my wife won't let me mortgage the house to buy one.

07-01-2009, 09:52 PM   #5
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How true, I wish the *lenses weren't so expensive they really are outstanding lenses but like you said you have take a second morgage to purchase.

thanks for the insight on the macro lenses, sounds like the 100mm is the way to go.

Thanks



QuoteOriginally posted by Canada_Rockies Quote
The 50mm would be of more use for someone photographing inanimate objects - stamps, jewelry, etc. The depth of field is roughly double at the same magnification and aperture, and the perspective is different as well.

The 100mm is a better choice for taking pictures of creepy crawly things that fly away when you get too close.

The FA* 200mm f/4 Macro would be even better, but my wife won't let me mortgage the house to buy one.
07-01-2009, 10:00 PM   #6
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QuoteOriginally posted by stl09 Quote
This may be a stupid question but what would be the difference between these two lenses? I know the f-stop is the same for both. Does one lens allow you to get closer to the object over the other.
I'm trying to figure what the advantage would be to have one over the other or should one have both lenses for macro shots?

Thanks,
Kevin
First, for comparing macro lenses, reproduction ratio is at least as important as focal length. If the 50mm and 100mm lenses can both achieve the same reproduction ratio, you can probably take the same shot with either one. You must get closer with the 50mm lens than the 100mm lens.

With a 50mm macro, size or weight is an advantage. These lenses are only a little bulkier than a non-macro 50mm prime lens. But getting extremely close is not always possible. Using a flash to add light may be more difficult because the camera and lens are in the way. Using a tripod may be impossible at those distances. On film, a 50mm macro might replace your 50mm normal prime kit lens and be the only lens you'd need. You could still do that with the Pentax DA 35mm f2.8 Limited macro, I suppose.

A 100mm macro can be inconveniently large, but worth the trouble if you need increased working distance. If you only have the shorter macros and need distance, you can only back up and end up shooting at a lower magnification.

For your first macro lens, think about what subjects you want to photograph, at what distance, then pick the best lens for that.
07-01-2009, 10:22 PM   #7
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QuoteOriginally posted by Canada_Rockies Quote
. . .

The FA* 200mm f/4 Macro would be even better, but my wife won't let me mortgage the house to buy one.
Nor will Marc divulge his address.
07-02-2009, 05:21 AM   #8
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Two differences seldom mentioned are:

1) field of view for the 100mm lens is about 1/2 that for the 50mm lens so when the object is at the same magnification, the 100mm's background is only 1/2 as wide as that for the 50. Therefore it is a little easier to compose in a way that avoids distracting backgrounds - just like the diffference between normal telephoto & wide angle shots.

The left photo was with a 50mm macro lens, right with a 90mm macro lens, both f4, same geometry.


Notice that the increased magnification of the long lens' background also makes the background look more out-of-focus; this is important when you want to isolate the subject.

2) it is twice as hard to hold the 100mm lens steady than the 50mm lens at the same magnification & f stop.The effective focal length for the 1/f speed rule is actual_focal_length times (1+magnification).

A Dave in Iowa


Last edited by newarts; 07-02-2009 at 06:28 AM.
07-02-2009, 06:47 AM   #9
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Also, I find the ultra-sharp D-FA 50mm more useful outside of the macro function. I found I used the 100mm for little other than macro shots, especially on the digital sensor. There are all sorts of trade-offs here.
07-02-2009, 08:11 AM   #10
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The 50mm is also a better bet if you are looking for greater than 1.0x magnification.
Example if you use a bellows unit and reverse a K100/4 macro lens you will get almost no increased magnification, if you reverse a K50/4 macro you can get over 3.0x magnification.
07-02-2009, 09:58 AM   #11
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QuoteOriginally posted by newarts Quote
The left photo was with a 50mm macro lens, right with a 90mm macro lens, both f4, same geometry.
That's an amazingly effective demonstration - thanks!

BTW, regarding the usefulness of the focal lengths for non-macro purposes - I actually find 100mm far more useful than 50mm. But that's because I also have a 28 and a 40 for use as "normal" lenses - I got these because I have a 50 but find it too long for most purposes. Whereas 50mm is also too short for portraits for me (not that I do portraits often). 100mm is on the long side for portraits (but still usable), but I find it *perfect* for concert photography, and long enough for general telephoto use (not wildlife) to replace a 135 in one's bag.
07-03-2009, 07:26 AM   #12
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QuoteOriginally posted by Canada_Rockies Quote
The 50mm would be of more use for someone photographing inanimate objects - stamps, jewelry, etc. The depth of field is roughly double at the same magnification and aperture, and the perspective is different as well.

The 100mm is a better choice for taking pictures of creepy crawly things that fly away when you get too close.

The FA* 200mm f/4 Macro would be even better, but my wife won't let me mortgage the house to buy one.
That's what everyone says but I'm leaning to the opposite direction. DOF on 100mm is WAY too thin even at f/16 and stopping down further (at least on my lens) starts to lose sharpness. Before I had my 100mm macro I took some great shots of bugs using a reversed 50mm which required slamming the lens on the face of the bug (roughly 20mm focusing distance).
07-03-2009, 07:54 AM   #13
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before, I was going after the 35 macro because I was looking for a sharp wide and a sharp macro as well. shooting macros though would be tricky since I would be shooting a few mm away from the subject (it's ok if it's an inanimate object). same dilemma with shooting with a 50 macro. though I was having some hard time deciding that one as well coz the macro in that one has the best IQ. but considering the fact that I have 2 of the best non-macro fast 50s, I decided to just then choose the 100 macro which is a very good macro lens but not as great as the 50 macro. I could live with that since I just need a lil bit of stop down and a lil bit of photo tweaking as well. plus gives me the versatility of a telephoto lens plus distance on shooting macros.
07-03-2009, 08:17 AM   #14
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as mentioned, the differences are: perspective (very interesting demonstration above, talking about background, i guess that's half of it when you talk about macro ); workign distance (very important for "disturbable" subjects). a very good point is which you would be more likely to use for things other than macro (i favour longer lenses, so it would be the 100 for me, it might not be for you, though). regarding dof, i tend to disagree, if i remember correctly, for macro purposes (close to 1/1 magnification), the magnification of the subject and the aperture will determine the dof, so actually a longer lens will allow you better dof, because you will be able to stop down further before difraction is a problem (however, i have yet to do "scientific" experiments on this subject ).

albert: i feel your pain, i have shot a 200mm on extension tubes, i loved it (though it is unconfortable, and of course, a dedicated macro lens would be better optically too, for macro). i see sigma is making a 180 macro, it's not cheap, but at least it's not ridiculous as the pentax 200 macro second hand.. (and i hear both sigma and tamron make excellent macro lenses), hope this helps a bit.

ps: why would you ever reverse a macro lens? reversing for macro only makes sense for "normal" lenses, as far as i understand, to try to get around the disadvantages of the "1 to many" optical design of a regular lens (turning it into many to one, which somehow seems to work better for macro)? or am i wrong?
07-03-2009, 10:04 AM   #15
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Don't forget the sigma 70 macro! Its the portrait length macro for Aps-c like the 100 macro was for film. Just like the 35ltd is a normal/macro for Aps-c where 50 macro was for flim.
Also you will probably find that manual focus is better for macro so one of the cheap but good 100macros is an option too
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