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Old Jan 4, 2008, 8:01 AM   #1
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I use a K10D. I need a 300mm (maybe 400mm) lens for wildlife photos. I have a Pentax SMC manual about 30 years old, 85mm-210mm f/4.5- f/32. I think it does well, but it lacks sharpness on many of my targets. Using a tripod is a must, and I use the two second delay for rather motionless targets. I hope to improve my shots of that nature.

Weight is not really a problem, nor is length, for most of my shots are taken around my home, where a tripod is convenient. My targets are usually fairly still, but on some I could probably take advantage of an instant-shutter triggering to avoid the delay while still getting no camera shake.

I don't think a macro feature is necessary, but don't think it will get in the way either, for I have the 18-55 kit lens and I presume it is Macro, and that it will provide any Macro I might need (? ? ?). Also, I have a set of Hoya close-up lenses for that lens.

What sort of triggering cable might suffice?

I am looking at these lenses:

Tamron AF 70-300 f/4- f/5.6 DI LD 1:2 Macro (new)

Tamron AF 75-300 f/4-f/5.6 LD Macro (new)

Sigma AF 70-300 f/4- f/5.6 DG Macro (new)

Tacumar 300mm f/4 SMC manual telephoto (used)

A similar lens with APO (new or used)

My questions:

Which of these is most likely to suit my needs? All are within my price range.

What do the terms DI, LD, DG, APO mean in this context?

Does AF signify automatic focus capability?

Does anyone know of other lenses that might be suitable, at a reasonable price?

This is a lot to chew on, but I really need the help of those of you who have the answers.

Thanks, Old Engineer
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Old Jan 4, 2008, 9:17 PM   #2
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Old Engineer wrote:
Quote:
I use a K10D. I need a 300mm (maybe 400mm) lens for wildlife photos. I have a Pentax SMC manual about 30 years old, 85mm-210mm f/4.5- f/32. I think it does well, but it lacks sharpness on many of my targets. Using a tripod is a must, and I use the two second delay for rather motionless targets. I hope to improve my shots of that nature.

Weight is not really a problem, nor is length, for most of my shots are taken around my home, where a tripod is convenient. My targets are usually fairly still, but on some I could probably take advantage of an instant-shutter triggering to avoid the delay while still getting no camera shake.

I don't think a macro feature is necessary, but don't think it will get in the way either, for I have the 18-55 kit lens and I presume it is Macro, and that it will provide any Macro I might need (? ? ?). Also, I have a set of Hoya close-up lenses for that lens.

What sort of triggering cable might suffice?

I am looking at these lenses:

Tamron AF 70-300 f/4- f/5.6 DI LD 1:2 Macro (new)

Tamron AF 75-300 f/4-f/5.6 LD Macro (new)

Sigma AF 70-300 f/4- f/5.6 DG Macro (new)

Tacumar 300mm f/4 SMC manual telephoto (used)

A similar lens with APO (new or used)

My questions:

Which of these is most likely to suit my needs? All are within my price range.

What do the terms DI, LD, DG, APO mean in this context?

Does AF signify automatic focus capability?

Does anyone know of other lenses that might be suitable, at a reasonable price?

This is a lot to chew on, but I really need the help of those of you who have the answers.

Thanks, Old Engineer
Hi OE,

I'll try to tackle a few of the questions, at least.

Definitions:

AF designates Auto Focus capability in all the 3rd party lens mfgs.

Di is Tamron's designation for lenses with digital optimized coatings which are designed to the extra flare that might arise in certain circumstances because of the extra reflectance of the sensor compared to film. They still cover a full 35mm frame, and have an aperture ring. Tamron's Di II lenses have an image circle set for APS-C sensored digital SLRs, and IIRC don't have the aperture ring. Sigma's DC = Tamron's Di and their DG lenses = Tam's Di II. Pentax's equivalents are Di=DC=D-FA, and DiII=DG=DA

LD is Tamron for Low Dispersion which = Sigma's APO (Apochromatic) and also = Tokina's SD (Super Low Dispersion). This means that the lens has at least one element that's made from special high performance optical glass which cuts down on chromatic aberrations (color fringing) caused by "normal" glass's tendency to refract light from different frequencies at different angles of refraction, thus splitting the colors like a rainbow refracted through a prism. LD glass does this to a lesser degree, so it's a desireable feature in lenses. BTW, Pentax's name for lenses with this type of glass elements is "ED".

About the lenses. Realize that I don't have any of these lenses. I do have an older model Tamron 70-300 LD Macro, but it's a different lens. From what I've heard, the Tamron 70-300 Di LD Macro and the Sigma 70-300 APO DG Macro are pretty comparable in performance, and both excellent buys. I believe that they both also made 75-300s, but in both cases, they were significantly outperformed by the 70-300 versions, and with the Sigmas, the APO is noticeably better than the non-APO.

The Takumar 300 f4 might be a little better optically, since it's a prime, but it's not the best of the Pentax 300s. The lens was significantly redesigned optically for the M*300/4 and A*300/4 versions which are sharper, smaller and lighter by some margin. The F* and FA* 300/4.5s added AF and ED elements to this and traded a little speed for much better balance, shorter min focusing distance, a noticeable increase in sharpness, and less CA. These * lenses do fetch premium prices tho, and with good reason.

If the Takumar is a bayonet mount, the Tak designation indicates that it might not be Super Multi-Coated (important to cut lens flare and light transmittance), as Pentax strangely chose to use the Takumar name for their bargain class lenses starting with the K mount, while in screw mount Takumar, and Super Takumar were used in their premium class lenses. The one plus for the Tak is that it's a stop faster, which may or may not be important to you. It's also probably considerably bigger and heavier.

Of all of these, I'd probably choose between the Sigma 70-300 APO and the Tamron 70-300 LD 1:2 Macro realizing that they might not AF well with even a 1.4x TC in bright sunlight.

For remote triggering, the Pentax F IR remote is very small and easy to carry, works to about 15 feet, and will trigger the shutter from both front and back with your K10 since it has sensors both front and back. Some find that it's too small tho -- and potentially easily lost -- your call. There are also some (Chinese?) IR units on ebay that are less expensive, but who knows of what qualtity? I have the Pentax.

There are also wired remote triggers. The Pentax one is the most expensive. The one that fits the Canon EOS camera also works perfectly, is less expensive, and is the one I own. The nice things about the wired triggers is that you can either hold the shutter switch down, or lock it down once triggered for either focus trap or Bulb setting shots. There are also Asian copies of these switches available on ebay for a lot less $$$, but again, it's a matter of perceived quality.

I hope this helps some. . .

Scott




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Old Jan 5, 2008, 1:59 AM   #3
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Scott, Thanks for the complete answer. I really appreciate it. I think I'll go for the Sigma 70-300 APO version. I like sharp.

Old Engineer
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