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04-08-2014, 10:51 AM   #1
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Beginner macro questions

Hi all,

I've been playing around with macro lenses and trying to read up here and there to figure things out as I go.
I've got a few questions that stand out so far:

1- I've been training myself to shoot in manual for the most part. What exactly does macro mode do, and when exactly should I be using it?

2- I was once taught that the only thing that separates a macro lens from a regular lens is the minimum focusing distance-- is this true?

3- Are macro lenses typically less suited for non-macro shots as compared to non-macro lenses? In other words, would it be silly to take a macro lens as a walk-around lens and use it for a bit of everything?
For example: I have the Tamron SP AF 24-135mm F/3.5-5.6 AD Aspherical [IF], defined by the company as macro, but in the reviews as "pseudo-macro." I use it for plenty of non-macro shooting. Is this a silly choice?

4- This is a question specific to that Tamron lens mentioned in Q3. There's a switch on the side of it to toggle between "aspherical" and "L." What exactly does this do, and does it have to do with macro vs. non-macro shooting?

Thanks so much for the help!
Danielle

04-08-2014, 11:20 AM   #2
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1. What is changing to macro mode? Some lenses have a 'macro mode' which lets you focus at closer distances when activated. Some cameras have a 'macro mode' which tell the camera to expect to have to focus very close and also to aim for a higher shutter speed and f-stop compared to it's 'normal' preferences to fight shake and narrow DoF.

2. That's one difference. Dedicated macro lenses usually have a flat field of focus, meaning the stuff in focus is an actual flat plane (or close to it). Most other lenses have some curvature here. This helps when photographing small, flat objects, like stamps for example. Dedicated macros also tend to be the sharpest lenses out there.

3. They work great at 'normal' distances too. My DFA 100mm gets tons of use at normal distances. If an autofocus macro lacks a focus limiter (which tells it NOT to focus close) like mine, then the autofocus can sometimes be a hassle if it misses focus and goes hunting as most macros will have a long focus throw down to their minimum focusing distance.

If you're happy with the results, it's definitely not silly Yours is not what many people would consider a 'macro' lens though, more of a 'general purpose zoom that can focus closer then most of the competitors in the same class'. Whatever the label, it's definitely in a different category from the dedicated macros out there.

4. I don't have that lens, but I think this is the manual www.tamron-usa.com/assets/pdfs/190d.pdf. It doesn't mention this switch, just a zoom lock for the Pentax model?
04-08-2014, 11:22 AM   #3
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QuoteOriginally posted by dfeld Quote
2- I was once taught that the only thing that separates a macro lens from a regular lens is the minimum focusing distance-- is this true?
A dedicated macro lens also has a flatter focal plane. Most lenses have a curved focal plane and that isn't ideal when working with very thin DOF because the center of a flat object will be in focus, but the corners won't.

QuoteOriginally posted by dfeld Quote
3- Are macro lenses typically less suited for non-macro shots as compared to non-macro lenses? In other words, would it be silly to take a macro lens as a walk-around lens and use it for a bit of everything?
For example: I have the Tamron SP AF 24-135mm F/3.5-5.6 AD Aspherical [IF], defined by the company as macro, but in the reviews as "pseudo-macro." I use it for plenty of non-macro shooting. Is this a silly choice?
There is no set definition for what "macro" really is, so manufacturers can slap it on anything that focuses relatively close. Zooms like yours are more suited to general shooting and also happen to focus close. I see the maximum magnification of that Tamron is 1:3.3, which is decent, but not really macro.

It is generally accepted that a real macro lens is a prime with a flat focal plane and a magnification of 1:2 or better with 1:1 being ideal. With a 1:1 macro lens at full magnification you'll be able to fill the entire frame with a subject the size of your sensor, 2416 mm in the case of the Pentax APS-C bodies. At 1:2 it would be 48x32mm and so on from there.

You can use a true macro lens for general shooting as well, but the auto focus ones are usually slow to focus unless they have a focus limiter.
04-08-2014, 11:54 AM   #4
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This doesn't respond to your specific question, but I thought you might be interested in this book on macro and close-up photography. I found it quite helpful. And unlike some photography books, it's relatively small (about 8" square), making it almost portable on a shoot.

Ammonite Press: The Expanded Guide, Close-up & Macro Photography AM-19851

04-08-2014, 03:03 PM   #5
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QuoteOriginally posted by dfeld Quote
4- This is a question specific to that Tamron lens mentioned in Q3. There's a switch on the side of it to toggle between "aspherical" and "L." What exactly does this do, and does it have to do with macro vs. non-macro shooting?
I think that may be a switch to keep the aperture ring in A position, so you can see and control the aperture on the camera. You can see if that's true; with the switch in L position, the aperture ring should be stuck on A. One of my Tamron lenses has a similar switch. It's easier and better to use the A position and camera body controls than the aperture ring.
04-08-2014, 04:55 PM   #6
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QuoteOriginally posted by elliott Quote
A dedicated macro lens also has a flatter focal plane
Let me clear up some misconceptions. The focal plane is inside the camera, not the subject you are shooting. All lenses have a flat focal plane with only slight deviations ( this is the aberration called curvature of field). There are only a few lenses with a flat subject field (some macros and projection lenses). Lenses without a flat subject field will have a spherical DOF. Macro lenses are corrected for spherical aberration at close distances when compared with non-macro lenses. So using them at infinity, especially wide open, puts them at a disadvantage to non-macro lenses. Macro lenses used for distant work are better if stopped down a bit to reduce the spherical aberration.
04-09-2014, 08:45 AM   #7
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Thanks everyone for the help. I've got some reading and shooting to do!
04-09-2014, 03:11 PM   #8
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One last point: manual focus with macro lenses (up close) is easy, and the old SMC Pentax-A 50 f2.8 and 100 f4 work great on Pentax K series cameras. I'll use them for my macro work over any of today's lenses, and they are bargains too. The -M versions are also excellent, if you don't mind M mode and "green button" for exposure.

04-09-2014, 11:19 PM   #9
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QuoteOriginally posted by dfeld Quote
4- This is a question specific to that Tamron lens mentioned in Q3. There's a switch on the side of it to toggle between "aspherical" and "L." What exactly does this do, and does it have to do with macro vs. non-macro shooting?
This is to lock the zoom barrels when fully retracted so they don't slide out with gravity by its own weight when you walk around while the lens points down. Also known to avoid zoom creep. Slide it to the L position and you find you won't be able to zoom as the barrels are now locked.

Also true macro lenses have a 1:1 magnification the Tamron has 1:3.3 magnification if I remember correctly. Lensmakers like to put Macro on their lenses to make them look better to prospective buyers.

Last edited by Schraubstock; 04-09-2014 at 11:28 PM.
04-10-2014, 03:34 AM   #10
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That's very funny you mention these, I actually have both of them (though the M version for the 100mm f4). I love the SMC pentax-A 50 f2.8 but haven't been playing with the 100mm as much... Need to get outside and practice with it.

QuoteOriginally posted by TomB_tx Quote
One last point: manual focus with macro lenses (up close) is easy, and the old SMC Pentax-A 50 f2.8 and 100 f4 work great on Pentax K series cameras. I'll use them for my macro work over any of today's lenses, and they are bargains too. The -M versions are also excellent, if you don't mind M mode and "green button" for exposure.


---------- Post added 04-10-14 at 06:35 AM ----------

Thank you!
I would not have guessed that. I was largely ignoring the L setting.

QuoteOriginally posted by Schraubstock Quote
This is to lock the zoom barrels when fully retracted so they don't slide out with gravity by its own weight when you walk around while the lens points down. Also known to avoid zoom creep. Slide it to the L position and you find you won't be able to zoom as the barrels are now locked.

Also true macro lenses have a 1:1 magnification the Tamron has 1:3.3 magnification if I remember correctly. Lensmakers like to put Macro on their lenses to make them look better to prospective buyers.
04-13-2014, 10:41 AM   #11
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Another question--
I hear a flash is in order for high quality bug shots. Any advice on a good flash that won't run me $400 like the macro ring flash? (Or is something like that really the way to go?)

Thanks!
Danielle
04-13-2014, 12:26 PM   #12
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Ring flash? HERE is my review. Looks like they are still available for $36 from China. As I note in the review, I tend to not use the flash mode but just use the light mode.
04-13-2014, 06:14 PM   #13
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Your Pentax-M 100mm f4 macro won't work with anything P-TTL - at least in the fully auto, flash does everything itself way that you spent the money for. A lens with an A position on the aperture ring (your other macro) or any autofocus lens, can use P-TTL.

The price and P-TTL limitations would make me consider one of those LED ringflash things, or a completely manual flash (or several). The continuous lighting option on the LED flashes would be easier to use with green-button metering. The very short burst of light from a regular flash freezes motion, so it's useful for substituting for shutter speed. Each type has a certain look. With some DIY creativity, you can build stuff to get the exact look you want.
04-14-2014, 06:06 AM   #14
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The constant light of the LED rings and panels lets you meter directly. I find flash with close macro typically overexposes, though I'm sure the more sophisticated ring flashes do better.

I've had much more luck with the constant light.
04-14-2014, 11:15 PM   #15
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QuoteOriginally posted by TER-OR Quote
The constant light of the LED rings and panels lets you meter directly. I find flash with close macro typically overexposes, though I'm sure the more sophisticated ring flashes do better.

I've had much more luck with the constant light.
I have one of those "cheapo" LED ringlights that spurred an idea - yes, the constant light mode is nice, but it still gives a flat, unflattering illumination to three dimensional objects. I plan to strip the control head off of mine and rewire the LEDs so that I have four separately controlled "quadrants" - top, bottom, left, and right. Each will be wired directly to the battery through a potentiometer so that each quadrant can be set individually to anywhere between full off and full brightness. I'll post sample pictures once I get around to wiring it up, hopefully in the next week or two.
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