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02-21-2013, 06:42 AM   #1
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Help me pic a focal length

Im looking at two macro lenses. a Sigma 70mm and a Sigma 105mm

If i got the 70 i would like to use it for portraits also.

If i got the 105 I can take it to the zoo and aviary and things as a nice telephoto.

I also have a Tamron 17-50 and a Pentax 55-300. Should I just get the 105 and mayb later ad a 35 or 50 for portraits? I dont know, i cant decide. I would probably use eith one just as much as the other, just differently.

02-21-2013, 07:10 AM   #2
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I'd get the 105. That's also a good portrait focal length.
02-21-2013, 07:12 AM   #3
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QuoteOriginally posted by GibbyTheMole Quote
I'd get the 105. That's also a good portrait focal length.
Thats the way I'm leaning. Plus if Pentax ever gets a Full Frame it will better yet.
02-21-2013, 07:12 AM   #4
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What sort of macro things are you looking to photograph? If you're looking to aim the macro at live skittish things like insects, longer is usually better. Nothing should stop you from using the 105mm for portraits.

02-21-2013, 07:14 AM   #5
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QuoteOriginally posted by BrianR Quote
What sort of macro things are you looking to photograph? If you're looking to aim the macro at live skittish things like insects, longer is usually better. Nothing should stop you from using the 105mm for portraits.
My house is little. Where i have my back drops, i only have about 12 feet. It was ok for head shots when i had a Tamron 90.

But it seems 105 is winning, I think im going to go order it. Thanks
02-21-2013, 07:21 AM   #6
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Well, you've already got your Tamron 17-50. That should be good for when you need a wider angle. And your 90 falls within your 55-300's range for when you need that focal length.

I shoot most of my portraits either with my Pentax A 35-105 or DA-L 55-300. Both are great for portraits.

If you're not dead-set on the Sigmas, the Cosina/Promaster/Vivitar/Phoenix 100mm / f:3.5 macro is a terrific 1:1 macro lens, (and general purpose & portrait lens) and is possibly a lot cheaper on the used market. Just make sure the matching diopter comes with it.

Last edited by GibbyTheMole; 02-21-2013 at 07:28 AM.
02-21-2013, 08:26 AM - 1 Like   #7
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The Sigma 105mm F2.8 EX DG Macro is my lens this month for the Single Challenge and it works great. There is a little purplefringing in extreme conditions att wide-open aperture, slow AF and it's pretty bad when it comes to flare with the sun in the frame. Though I had to tighten the mount now as it lost connection with the camera but it was easy.

Here are some results:











On my Pentax Q with an adapter:
02-21-2013, 08:36 AM   #8
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QuoteOriginally posted by VisualDarkness Quote
Here are some results:
Beautiful shots there! I'm especially fond of that 1st one. I'm gonna have to break out my macro stuff more often.

02-21-2013, 08:39 AM   #9
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Does the Q get you more magnification than 1:1 from its smaller size. That ice sculpture photos sure is magnified.
02-21-2013, 09:28 AM   #10
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QuoteOriginally posted by no694terry Quote
Does the Q get you more magnification than 1:1 from its smaller size
Oh yeah... You can get near microscopic levels of magnification with a macro lens on a Q, but you need to have a really steady support for the camera.

Here's a human hair shot with the Q:


Record grooves:


Tip of fine sewing needle:


I was experimenting, so they're not awesome shots or anything... but they show what's possible with the Q.
02-21-2013, 09:39 AM   #11
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QuoteOriginally posted by GibbyTheMole Quote
Oh yeah... You can get near microscopic levels of magnification with a macro lens on a Q, but you need to have a really steady support for the camera.

Here's a human hair shot with the Q:

Record grooves:

Tip of fine sewing needle:

I was experimenting, so they're not awesome shots or anything... but they show what's possible with the Q.
Excellent! You're going to make me get that q-to-K converter in the end, mainly for my A* 200 f/4 macro = 1100mm f/4 5.5:1 macro! :P
02-21-2013, 09:47 AM   #12
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QuoteOriginally posted by miles Quote
You're going to make me get that q-to-K converter in the end, mainly for my A* 200 f/4 macro = 1100mm f/4 5.5:1 macro!
It's fun, for sure. On those shots above, I used a Promaster 100mm / 3.5 macro lens with a Pentax M 50mm / 1.7 reversed on the end of it. The Pentax adapter is nice, but too spendy for me. I just use the $30 Fotodiox adapter with aperture ring. Does the job.
02-21-2013, 09:53 AM   #13
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The Siggy 70 is one of the sharpest lenses. Also full frame. ...just to confuse the matter!
02-21-2013, 11:39 AM   #14
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QuoteOriginally posted by GibbyTheMole Quote
Beautiful shots there! I'm especially fond of that 1st one. I'm gonna have to break out my macro stuff more often.
Bring a flash or a tripod though! 1, 3 and 4 are taken with a Sigma EF530 DG on the camera, nr 5 is a two flash setup and the other ones with a tripod.
QuoteOriginally posted by no694terry Quote
Does the Q get you more magnification than 1:1 from its smaller size. That ice sculpture photos sure is magnified.
Not more than 1:1 as it only says that the image is projected "life-sized" 1:1 on the sensor and the sensor size has nothing to do with it. The image is merely croped compared to a bigger sensor as long as the distance to the sensor and the lens is the same. Though the higher pixel density of the Q makes each pixel capture smaller details mking it capture more than a cropped shot from the K-5 with the same lens.
So all in all you get smaller details in the shots which ables you to show smaller things but with the expense of some handling.
02-21-2013, 12:08 PM   #15
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About that Q-to-K adaptor...

QuoteOriginally posted by GibbyTheMole Quote
It's fun, for sure. On those shots above, I used a Promaster 100mm / 3.5 macro lens with a Pentax M 50mm / 1.7 reversed on the end of it. The Pentax adapter is nice, but too spendy for me. I just use the $30 Fotodiox adapter with aperture ring. Does the job.
Aaah, i thought that was even more microscopic! Any guess on what magnification you are achieving?
Is there really a benefit with the Pentax adaptor? Can i adjust the aperture on an A or FA lens with a fleabay adaptor? Is that aperture ring for DA lens? I don't think the rolling shutter thing will be a big deal for me - i don't do much video anyway... many thanks!
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