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04-10-2012, 05:05 AM   #1
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100mm SMC M f4 or f2.8

Which lens should I get?
The f2.8 seems to be cheaper.

04-10-2012, 05:20 AM   #2
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These are rather different beasts; the f4 is a macro lens. Are you interested in macro shooting? The f2.8 is, of course, a faster lens. Do you need the extra speed, or the thin depth of field possibilities?
04-10-2012, 05:28 AM   #3
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I was looking for a macro lens
04-10-2012, 05:35 AM   #4
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OK, just to be clear, if the f/2.8 lens is the Pentax-M, it is not macro. There are 100/2.8 macros from Pentax (and others), but they are generally going to cost more than the Pentax-M 1:4 100mm macro.

04-10-2012, 06:19 AM   #5
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I have the 100 f4 macro and love it. It's extremely sharp, and can be found for under 100 bucks. It only does 1:2, but you can still get some really good closeups with it.

Last edited by bluestringer; 04-10-2012 at 03:40 PM.
04-10-2012, 12:21 PM   #6
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Agreed. These are two very different lenses. The M100/2.8 would be an excellent long portrait lens and a cheap 85mm option. I have the M135/3.5 and the min focus distance (mag factor) is a limiting factor. Pretty much impossible to do macro or close focus w/o tubes. the M100/4 is at the top of my wish list as a versatile telephoto. It will take a nice portrait but it's an outstanding macro lens and a useful macro distance. My M50f4macro is too short for a lot of things I want to do.
04-10-2012, 12:30 PM   #7
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04-10-2012, 12:32 PM   #8
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Pentax M 100mm f/4 Macro works for me

I've used it for copy work and macros. Pretty sharp at all apertures...

Best regards

04-10-2012, 12:39 PM   #9
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the M100 2.8 is a nice small inexpensive portrait and low light option. it can suffer some pretty nasty PF though (as i discovered shooting a woodpecker in a tree in early spring)

without tubes though it's no macro

the m100 f4 is a pretty decent compact Macro from what i have seen though it needs tubes to be 1:1 as well, (50mm auto extension tube)

The Legendary A 100 2.8 is a true 1:1 macro and fast but it sells for a tonne of dosh

the F 100 2.8 is 1:1 and fast and AF and sells for about half the price of the A (though still 3 X the price of the M100 F4) - the FA 100 sells for similar pricing but adds a focus limiter - essentially it is the Predecessor to the current DFA at half the price

Edit If you are looking manual focus you should look at the Lester Dine 105 2.8 - prices have gotten a little silly lately but it is an excellent macro (it was the Dentist lens of choice in the past)
04-10-2012, 01:37 PM   #10
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100mm Macro shoot-off ...


I went and did a silly thing last weekend at a swap meet ... pick up a M 100 f4 Macro. Just saw it and boom, had to have it ... and soon I will have maybe a shoot-off between it and the D FA 100 f2.8 Macro WR. Maybe not a fair competition, but I want to play with the "M" macro (1:2) with some tubes, etc., since it has an Ap ring ... and like I said, I did a silly thing ... damned LBA! Any suggestions ... any input is appreciated for the future tubes et al.

Salut, J Frog
04-11-2012, 04:21 AM   #11
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My Choice

Hi Ollie,
If you're looking for a good macro for around $100.00 USD, the Pentax M 100mm Macro is a great choice.
Here's a few samples from last weekend, shot with a Pentax K-7 + the M100 f/4.0. no filters or extensions, just the camera and lens, hand-held.
Attached Images
View Picture EXIF
PENTAX K-7  Photo 
View Picture EXIF
PENTAX K-7  Photo 
View Picture EXIF
PENTAX K-7  Photo 
View Picture EXIF
PENTAX K-7  Photo 
View Picture EXIF
PENTAX K-7  Photo 

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