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Old Mar 25, 2007, 12:51 PM   #11
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As Scott mentioned, I have the 100mmPhoenix and really like the optics. It came down to either buying some extension tubes and using my 50mm 1.7 or buying a true macro lens. Since the Phoenix wasn't much more expensive than B&H's price for extension tubes, and it can focus to infinity (without the adaptor), I chose to go that way. If you have a need for a fast lens, it might make more sense to buy a used 50mm 1.4 or 1.7 and exension tubes - then you have a sharp lens for low light as well as macro. It would probably cost more than getting a Phoenix lens, but adds the low-light capability. Otherwise, you can get very acceptable results with the Phoenix. If you are using it strictly for macro, don't bother with the FA version - the auto focusing mechanism seems flimsy and it hunts more than any of my other lenses. Besides, macro really is done with manual focus.

Extension tubes cut down the light available, so if you use one on a slow lens, it becomes even slower - makes things difficult with moving bugs (answer - use a flash) - the reason why most people talk about the 50mm 1.7 r 1.4 when they talk about extension tubes.
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Old Mar 26, 2007, 9:02 AM   #12
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Rodney, extension tubes will work on all lenses, but it depends on which ones you get.
Basically there's 3 types.

- The best and most expensive have all the electrical contacts so they will allow the lense to work exactly as it does on the camera (Av, Tv modes etc). These are the ones you'll need for the 18-125mm lense and possibly the other, I'm not sure.
Can't find an example since they are quite rare, and therefore, quite pricey when one does show up.

- The 2nd type don't have the electrical contacts, so your lenses will either be fully stopped down, or wide open, neither of which are ideal for macro work. These tubes are only of use if you have a lense with an aperture ring (like the 50mm's)
These will allow you to use only the M mode.

- The 3rd type are the cheapest because they don't have the electrical contacts (type 1) or the mechanical connection (types 1 + 2)
Again you will need a lense with an aperture ring.
A disadvantage of these tubes are that if you set your aperture at for example f16, the viewfinder will be very dark (a problem you don't have with type 1 + 2 as they have the mechanical aperture lever)
There is an advantage over type 2 however. You can use Av mode so the shutter speed is adjusted automatically.

In summary, If your lenses don't have an aperture ring you're better off buying a 50mm lense (which is a great lense used on its own anyway and highly recommended) and a set of the 2nd type of extension tubes.
The ones I linked to are going to go for quite a bit since they are Pentax, but any brand will work just as well since there's no optics involved at all.

I was in a similar situation to you, I have the 18-125mm too and decided to go this route instead of the expensive tubes for the lense. I'm very happy and to be honest, I'm pretty sure the results from the 50mm would be a lot better than from the 18-125mm

I hope that helps
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Old Apr 1, 2007, 6:23 AM   #13
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Well thankyou everybody, I think I should buy a true macro lens.
As I said I have now the Pentax K100D with the Sigma 70-300mm 'APO' DG Macro lens and also the Sigma 18-125mm.
I want to photo insects, some flowers and close ups of animals.
Which I these would you say suit me best ---

Sigma MACRO 50mm F2.8 EX DG , $AU 620
Sigma 70mm f/2.8 EX DG Macro AF $ ???
or maybe the
Leica 100/2.8 APO $US 3,295

or something else ( I can not find any Phoenix here )

I cannot decide, the Tamron gets very good reviews for it's portrait and macro abilities, what would compliment best what I already have ?

Thankyou for all your help, I appreciate your opinions and advice,
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Old Apr 1, 2007, 8:55 AM   #14
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For insects, I would recommend a90mm, 100mm, or 105mmover a 50mm macro. I have no experience with the Sigma 70mm at all.

If your budget is tight, B&H has a used Promaster 100mm f3.5 in stock for $75. I believe that is the same as the Phoenix.


Here is the same lens on ebay under the Vivitar name:


B&H does carry it new under the Phoenix name as well for $120.00

My recommendation would be to spend a little more on one of these lenses, all of which have excellent reputations as macro lenses.




I would expect the Tamron 90mm you have listed to do very well, just make sure it does true 1:1 macro.

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