Macro lenses?

[knightmg1983]

Not sure if this is the right place but here goes.
I am somewhat confused by the concept of macro lenses. Is there a clear way that they are classified? All the lenses I see are clasified by the focal length.

Im not sure if I'm right but the focal range can be different for lenses of the same focal length?

I guess my question is how would you know if your buying a true macro lens or just a so-so macro lens? How would you know if it is truly 1:1, more or less?

[Mr Guy]

Very broadly speaking, macro lenses have two things in common. The first is that their minimal focal distance, ie the distance from end of the lens to the subject, is usually fairly small so you can creep right up on your target. Secondly, the combination of the focal distance and the focal length on macro lenses means that you can get "life sized" images on the sensor/film. A good chunk of macro lenses are actually 1:2 though, meaning they can make the image on the sensor half the size of the true size of the subject.

In the description of the lens, the numbers you're looking for are where it says 1:1, 1:2, 1:3 and the word "Macro" to designate a macro lens.

I don't know if it's true on other bodies, but the majority of what's available as true macro lenses for Pentax are prime lenses. For strictly digital, the best option is:

SMC Pentax-DA 35mm F2.8 Limited Macro (For Pentax, the Limited means it's just a little bit awesome, metal bodies, best optics, etc)

There's also two full frame prime autofocus lenses that are macro:

SMC Pentax-D FA 100mm F2.8 Macro
SMC Pentax-D FA 50mm F2.8 Macro


Of course, if you aren't hung up on it also being an autofocus lens or a Pentax branded lens, there are a ton of options:

Macro Search at Pentax Forum's lens database

[knightmg1983]

Thanks for the help. I was looking at ebay and such but most are just described by the focal length. I suppose more research is in order. The question arose looking at one of the lenses I have, it calls itself a macro lense but the markings only go to 1:4. I wanted to find more information as to wether or not it would be worth purchasing a true macro lens.

Thanks for the help. I think this supports my thought that a "real" macro lens would make quite a bit of a difference. I would probably be looking for an older manual focus lens. I like them so much more they seem to be more solid and they make me think.

Thanks again. Have pleny of time to do my research.

[Mr Guy]

Glad I could help, PentaxForums, linked above, has a really database of lenses that you can use to filter out what to look for on ebay. I just wish you could sort it a little easier.

[goodgollycr]

So, 1:1 is better than 1:2, right?

[Mr Guy]

Better in the sense of larger subject size to image size, yes.

[Ffred]

All macro lenses are primes. Macro is 1:1 or better (rare, unless you add spacing tubes), meaning your image is real size on the sensor. Technically if it's smaller it isn't macro.

There are no real macro zoom lenses. Although you can take "proxiphoto" images with a zoom that are good as well. Up to you.

The focal length of macro lenses changes the distance you have to be before you can focus, the longer the focal length, the further you can be, but the harder it is to focus. So it depends on what you want to take pictures of. A mid-range lens, like a 90 or a 105 is usually a good compromise, but then again it depends on your needs.

Third party lenses (from Sigma and Tamron) are quite good and might be less expensive than the Pentax ones.

Macro lenses are of course also excellent "regular" primes.