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12-15-2013, 01:48 PM   #16
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QuoteOriginally posted by tromboads Quote
Why doesn't anyone here champion extension tubes?
The OP is asking about 3 specific lenses. If he asked about macro options, there may different responses.

12-15-2013, 01:49 PM   #17
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QuoteOriginally posted by tromboads Quote
Why doesn't anyone here champion extension tubes?

They're a pain in the butt, and they loose a lot of light very very quickly. I'd guess you'd need a 85mm F/1.4 to approximate a 100mm F/2.8 macro... and those lenses aren't cheap.
12-15-2013, 01:54 PM   #18
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SMC Pentax-FA 100mm F2.8 Macro

Probably my best lens. Not ideal for portraits and not small. Works with flash, autofocus with limiter, and sharp.
12-15-2013, 04:32 PM   #19
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QuoteOriginally posted by tromboads Quote
Why doesn't anyone here champion extension tubes?
No, my ex-wife has mine, I hate even thinking about them.., you had to ask.

QuoteOriginally posted by Tako Kichi Quote
Earlier this week I received a Sigma 105mm F2.8 EX DG macro lens and so far I've been very impressed with it just taking test shots around the house. It's a true 1:1 lens, pin sharp, has focus limiting and the front element is flat-field so it can be used for thin/flat objects like stamps or coins without distortion in the corners.

I was lucky enough to find it on Ebay as 'new old stock' (NOS) complete with a 7 year Canadian warranty and paid less for it than I've seen some used ones going for recently. Talking of used there is at least one Sigma 105mm F2.8 EX DG macro currently for sale on the Market Place here and would be a great buy for anyone after one. https://www.pentaxforums.com/forums/24-photographic-equipment-sale/243291-sal...-dg-macro.html

The lens gets great reviews on all the lens review sites and the PF review can be found here. Sigma 105mm F2.8 EX DG Macro Lens Reviews - Sigma Lenses - Pentax Lens Review Database

P.S. the lens has been discontinued in Pentax K mount so you can only find it used now (or NOS if you are very lucky, like me).
That Sigma 105 is probably the best rated of them. But in my family we have the Tamron 90 and Sigma 70, I like the 70 for head shots as well as Macro…the 90 and 100 might be a bit long for that. The Sigma 70 is a great lens, but it's heavy compared to the Tamron, and I'm guessing heavier than the 100 as well. Apart from the weight, I can't say a bad thing about the 70, and the wife never says a bad thing about the Tamron 90. And no one ever says bad things about the 100 either. Starting from scratch, this would be a tough choice. Depending on what other primes you have, if you had a 50mm as your longest prime, you might want the 100 just to extend your reach.

12-15-2013, 05:17 PM   #20
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QuoteOriginally posted by tromboads Quote
Why doesn't anyone here champion extension tubes?
Ok...I will!

A set of cheap extension tubes when paired with a decent prime lens provides an excellent solution for macro shooters.


Steve
12-15-2013, 05:22 PM   #21
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QuoteOriginally posted by ElJamoquio Quote
They're a pain in the butt, and they loose a lot of light very very quickly.
The light loss is no more than the extension of a dedicated macro lens. That is the unspoken truth about all macro lenses. The marked focal length and maximum relative aperture (f-number) are the values at infinity focus. Go down to 1:1 and the working focal length is quite a bit longer with a concomitant loss of light to the viewfinder and sensor.

That is why TTL metering is so useful for macro work and is the case regardless of how you get the extension. If you do 1:1 with a view camera, you need to calculate in the exposure compensation for the extra extension. That is one advantage to auxiliary close-up lenses.


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12-15-2013, 05:24 PM   #22
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QuoteOriginally posted by normhead Quote
No, my ex-wife has mine, I hate even thinking about them.., you had to ask.
Pity. There is nothing worse than to have one's ex have possession of one's means to extend.


Steve


(...sorry could not resist...)
12-15-2013, 05:26 PM   #23
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QuoteOriginally posted by normhead Quote
Apart from the weight, I can't say a bad thing about the 70
The 70 has the best resolution of Sigma's macro offerings (or at least it used to). I own the 50/2.8 EX DG Macro and wished at the time I bought it that I had the funds for the 70.

For what it's worth, the working distance with a 50mm lens is pretty bad. I love my Sigma 50, but wish it was longer.


Steve

12-15-2013, 05:52 PM   #24
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QuoteOriginally posted by ElJamoquio Quote
They're a pain in the butt, and they loose a lot of light very very quickly. I'd guess you'd need a 85mm F/1.4 to approximate a 100mm F/2.8 macro... and those lenses aren't cheap.
I agree, that's twice in one day.
12-15-2013, 07:54 PM   #25
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QuoteOriginally posted by tromboads Quote
Why doesn't anyone here champion extension tubes?
I use a 50mm tube to make my M 100/4 go to 1:1, to make my M 400/5.6 focus closer than 5m (16.5 ft). However, the downside of extension tubes over (under?) macro lenses is that the lens is not flat field.
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