[dndcdr]

Baught the K-5 and the 200mm 2.8 DA* I found out before I baught the lens that t is actually an FA lens. I have decided to purchase all FA lenses from now on.

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Last edited by dndcdr; 03-22-2012 at 01:50 PM.

[Patajac]

Why is that?

[dndcdr]

not sur why. I think it's because Pentax has a 50-135 DA* which means that it is equal to 202MM with the crop factor. Why have a zoom equal to 202MM and a telephoto at 200MM? The 200mm DA* 2.8 will be aprox equal to 300MM on an APS-C. I tried the 20MM on a film camera, and the viwfinder looked normal. If I ever get a FF DSLR, I will have the proper lenses.

[SpecialK]

not sur why. I think it's because Pentax has a 50-135 DA* which means that it is equal to 202MM with the crop factor. Why have a zoom equal to 202MM and a telephoto at 200MM? The 200mm DA* 2.8 will be aprox equal to 300MM on an APS-C. I tried the 20MM on a film camera, and the viwfinder looked normal. If I ever get a FF DSLR, I will have the proper lenses.

Well, the last sentence is accurate. However, that 50-135 will always be shorter than 200. The type of lens is immaterial as the crop factor is a function of sensor size, not the lens type.

[dndcdr]

I understand that, It just seems strange to offer a 135mm with a crop factor of 1.5 then offer a DA* lens which is 200mm. makes no sense. Not sure why the 200mm says DA* on it when it is actually a lens which can be used on film cameras and the FF when it eventually comes out. I will buy FA* lenses so that if I ever decide to get a FF Pentax, I will already have the artillery

[DAZ]

Your statement leads me to believe you don’t get it. A 135 mm is always a 135mm and a 200 mm is always a 200 mm. The DA* 50-135mm is not the same as the DA* 200mm even if it will cover the image circle of a 135 format (full frame 35 mm film). At 135 mm on an APS-C the angle of view is about 10 degrees and the 200 mm is 6.8 degrees. On a 135 format it is 15 degrees and 10.3 degrees.

DAZ

[dndcdr]

I purchased the 200mm DA* 2.8 I was debating between it and the 50-135. I prefer fixed focal length lenses. I will use the 200mm for outdoor sports and a smaller lens for basketball and volleyball. I think the K-5 and the 200mm were around $1,975. I thought is was a good price.

[zapp]

The 200 mm lens has an equivalend angle of view of a 300 mm lens on your digital Pentax.
The 50-135 has an equivalent angle of view of a 70-200 mm lens on your digital Pentax.

The 50-135 is NOT a 70-200 mm lens and the 200 mm is NOT a 300 mm lens - just because the APS-C sensor in digital Pentax cameras crops the image you end up with a narrower field of view similar to a longer focal length lens on a full 24 x 36 mm2 sensor.

The 200 DA allows full frame coverage, the basic design is from full frame days, so it is easy to adjust (same holds for several lenses, but not wide angle lenses). The lack of an aperture ring makes it useless on most older cameras.

[RioRico]

To reiterate what's been said: Lenses neither stretch nor shrink when moved between cameras. A lens projects an image; different-size frames (film or sensor) capture different-size portions of that image. A 100mm lens remains 100mm no matter where it is.

Unless you are an experienced 135/FF togger who is making a transition to APS-C cameras, and so would like a mental tool for comparing AOVs (angles of view), you should forget that you've ever heard of a crap.factor. The term, like 'equivalence', causes endless confusion.
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ObTopic: FA and DA lenses have different strengths. DAs: usually smaller; can be shorter. FAs: can be used on FF cameras; usually perform better on APS-C cams because the smaller sensor captures the lens' "sweet spots". And FAs don't have the problematic SDM motor.

Don't be afraid to look at F lenses also. One of the best deals around is the tiny agile sharp F35-70 for around US$50. The F35-70 has been called an ideal "backyoard lens", great for shooting kids and pets and flowers. I'll sometimes carry a kit of the Tamron 10-24, F35-70, and FA100-300 (silver).

[mattt]

Surprisingly, with all the discussion above about equivalence and Fields of view, no one commented as to whether vignetting will occur with the newly procured DA* should a future Full Frame formatted K mount digital body ever materialize. Any of you have knowledge of that?
Also surprisingly... no discussion on the variety of coatings SMC lenses get depending on weather they are designed from a Film body or a digital body. My understanding is there is different treatments for DA lenses when compared to FA type.

[RioRico]

Surprisingly, with all the discussion above about equivalence and Fields of view, no one commented as to whether vignetting will occur with the newly procured DA* should a future Full Frame formatted K mount digital body ever materialize. Any of you have knowledge of that?

Since Pentax-Ricoh has said zilch about any potential FF, we have no knowledge. We can *speculate* that a K-FF will have some internal cropping to handle APS-C lenses. We can *hope* that a K-FF might eventually emerge. But we know nothing.

Those who know, don't say. Those who say, don't know.

Also surprisingly... no discussion on the variety of coatings SMC lenses get depending on weather they are designed from a Film body or a digital body. My understanding is there is different treatments for DA lenses when compared to FA type.

I've read that. I don't know how significant that is for FF lenses used on APS-C cameras.

[dndcdr]

I tried the 200mm on a film camera, the view finder was clear. I purchased the 200MM because I needed the reach and becaude it can be used on FF if I ever choose to. I see no point in buying DA* lenses unless you want to cut down on weight. The 200mm will be my bigest lens. I can hirelarger lenses if I know I might need them.