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10-30-2008, 07:44 AM   #1
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macro shooting with small focal length lenses

i had a 70-300mm and am waiting for my 18-250mm and can take some nice macro shots with that considering the zoom is fairly big. i'm curious to know how exactly you can shoot macro with a 50mm or 35mm and still be able to get wicked crisp images of animals like bees and others that move when you get too close :S


Last edited by pete_pf; 10-30-2008 at 08:48 AM.
10-30-2008, 08:33 AM   #2
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I'm curious about this too - I imagine those lengths aren't very useful for getting shots of anything alive. The 35mm has something like a 2cm focus distance at max magnification. You are pretty much touching the subject with the lens hood at that point.
10-30-2008, 08:51 AM   #3
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This is about as close as I normally get with my DA35mm Limited (taken with K100DS):




If you crop to 100%, you basically get the same FOV as if you'd used a longer focal length. This is a 100% crop of the above shot:

10-30-2008, 08:55 AM   #4
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Wow, nice pics! Do you know about how far away you were from the flower for that shot?

10-30-2008, 09:19 AM   #5
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For macro work, you really need a proper macro lens, i.e. one that produces at least a 1:1 image. In my experience, for small insects, e.g. hoverflies, or even larger insects such as dragonflies and butterflies, a 100 mm or better still a 180 mm macro (equivalent to around 270 mm in 35 mm terms due to the cropping factor on an APS sensor) is ideal since it keeps you a sufficient distance from the subject so that you do not frighten it away.

Another advantage of standing off from the subject and not trying to fill the frame is the problem of depth of field. When operating in macro and near 1:1, the depth of field is very narrow and if you try to fill the frame, only a very small part of the subject will be in focus. Sean's image illustrates that. Even at the distance the original image was taken, from the crop you can see that only part of the body and one wing are in focus. In most cases, it is most important to ensure that the eye is in focus since this is a point of interest that the viewer is drawn to. A tripod is really essential!

It takes a lot of practice and, even more important, patience, to get good images of insects. I am not sure that the 18-250 lens is the best one for macros. Try and pick up a secondhand manual focus 100 mm macro lens - it doesn't matter that it is manual focus as autofocus doesn't really work well with macro work.

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10-30-2008, 09:50 AM   #6
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QuoteOriginally posted by brownargus Quote
I am not sure that the 18-250 lens is the best one for macros.

John
I've used the 18-250 for a variety of things, and while I'll agree that there are better macros out there, it is actually not bad. You have a decent amount of working distance available, and the magnification (1:2.7 i think) is pretty good for such a superzoom. I'd say it is a good way to start to get familiar with macro work, although for anything serious you'll obviously want a dedicated lens.
10-30-2008, 11:22 AM   #7
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The 18-250 is fine for flower head sized shots, but hopeless for insect-sized macro.
10-30-2008, 12:09 PM   #8
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QuoteOriginally posted by Eigengrau Quote
Wow, nice pics! Do you know about how far away you were from the flower for that shot?
The bee kept moving from flower to flower and I had to keep repositioning - so I'm not 100% sure of the distance, but my guess would be about 3-4 inches or so.

For formal work with a tripod you can get much closer, but hand-held shots are difficult because slight camera movements cause big changes in focus plane, image composition, and also effectively render SR useless.


Last edited by Sean Nelson; 10-30-2008 at 12:20 PM.
10-30-2008, 12:13 PM   #9
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QuoteOriginally posted by brownargus Quote
Another advantage of standing off from the subject and not trying to fill the frame is the problem of depth of field.
Depth of field is the same at macro distances, no matter which lens you use. A 35mm, 50mm or 100mm macro lens will give the same depth of field at the same f-stop (f/5.6, for example), assuming you position yourself so that the subject fills the same amount of the frame for each shot. This is because the smaller depth of field of the longer lens is offset by the farther distance you need to be at in order to achieve the same subject size.

However you have the potential for larger depth of field with a longer lens because you can stop it down to a smaller f/number before diffraction starts to be an issue.
10-31-2008, 05:21 AM   #10
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QuoteOriginally posted by Sean Nelson Quote
Depth of field is the same at macro distances, no matter which lens you use. A 35mm, 50mm or 100mm macro lens will give the same depth of field at the same f-stop (f/5.6, for example), assuming you position yourself so that the subject fills the same amount of the frame for each shot. This is because the smaller depth of field of the longer lens is offset by the farther distance you need to be at in order to achieve the same subject size.

However you have the potential for larger depth of field with a longer lens because you can stop it down to a smaller f/number before diffraction starts to be an issue.
I was not aiming to get the same image size with a longer lens. However, using the same lens at twice the distance increases the DOF because the reproduction ratio is changed. For instance, with an insect with large antennae, e.g. a longhorn beetle, it is impossible to get the insect and antennae in focus at near life size. However, if you step back until the whole insect is in focus and then crop the image later, the whole insect stays in focus. Accepted, you suffer some loss of definition because of the lower pixel count due to the crop, but that is one of the advantages of cameras with a larger pixel count.

John
10-31-2008, 05:57 AM   #11
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For macro work, you really need a proper macro lens, i.e. one that produces at least a 1:1 image 100 mm or better still a 180 mm macro lens
10-31-2008, 12:39 PM   #12
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QuoteOriginally posted by impete82 Quote
i had a 70-300mm and am waiting for my 18-250mm and can take some nice macro shots with that considering the zoom is fairly big. i'm curious to know how exactly you can shoot macro with a 50mm or 35mm and still be able to get wicked crisp images of animals like bees and others that move when you get too close :S
This spider has a body about 5mm across.

Carl Zeiss Jena 35/2.4



smc Pentax-M Macro 50/4



smc Pentax-A 70-210/4 @ 210



I don't have a way to use my flash off camera so the most immediate issue is that I could not use the flash with the A70-210. It also meant that I had to have the aperture wide to get a long enough shutter speed hand-held and hence this results in the narrow DOF. The spider was in my greenhouse and so the closest focus of 1.2m for this lens was a pain because I had to try and avoid the other stuff in the greenhouse <g>

There's never a need for a hood with the 50 Macro f4 because the front element of the lens is recessed so far back. Similarly, for macro work there's no need for a hood on the CZJ 35/2.4. So in those cases I can get in close - a few cm away. With shorter FL I can have longer shutter speeds handheld and so I can use smaller apertures. Since those shorter FL lenses have short barrels (and no hood) it means that I can use on on-camera flash (in both cases here, the K100D flash with some tissue wrapped over it to reduce the light). Using a flash means I can use a much smaller aperture and hence get a better DOF.

Getting in close means being patient and not making any sudden moves. The spider got spooked with the CZJ shot and "hid", but for the M 50 Macro shot I was just as close, but I was more careful.

Other than the ability to get in closer (23cm for M50/4 compared with 45cm for M40/1.4), I've read that the M 50 Macro has a flatter field that none macro 50's. I have not tested this.

Richard
10-31-2008, 05:09 PM   #13
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QuoteOriginally posted by brownargus Quote
However, using the same lens at twice the distance increases the DOF because the reproduction ratio is changed. For instance, with an insect with large antennae, e.g. a longhorn beetle, it is impossible to get the insect and antennae in focus at near life size. However, if you step back until the whole insect is in focus and then crop the image later, the whole insect stays in focus.
I think you're mistaken there. Cropping is exactly the same as using a longer focal length lens - if you crop the image so that the subject fills the frame it's going to have the same depth of field as if you had taken it with a focal length long enough to have the subject fill the frame (assuming the same f/number was used for both shots).

Have a look at my two macro pictures posted above. In the full-frame version the bee looks to be mostly in focus, but in the cropped view you can see that only part of it is.
10-31-2008, 05:36 PM   #14
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just got the lens today, went for a walk trying it out, it's not the worst thing actually hehe :P i will get a true macro in the future but having the 18-250 is utterly sweet for nature shots (can jump from landscape to close up), then gatta get my 50mm 1.4, then i'll get a super duper macro
10-31-2008, 06:10 PM   #15
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QuoteOriginally posted by impete82 Quote
i had a 70-300mm and am waiting for my 18-250mm and can take some nice macro shots with that considering the zoom is fairly big. i'm curious to know how exactly you can shoot macro with a 50mm or 35mm and still be able to get wicked crisp images of animals like bees and others that move when you get too close :S
One uses the focal length best suited to the scene if possible. If the 35mm lens is too short, then one should have a longer one on hand.
If the subject will sit still then objectively it really doesn't matter what focal length is used, focal length being an aesthetic decision more often than not, and all.
I don't know how good the 35mmLTD is at distance, so I don't know if it is a good general purpose lens.
If it is, then it would be a good walkaround lens, as the close focusing ability is handy, even if one isn't shooting bugs and flowers all the time.
I do think a macro in the 100mm range is a better macro focal length, but it is also a more specialized focal length.
Overall, a 35mm lens is more useful than a 100mm lens.
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