[mrsnoogle]

hey there....
I have been offered a pentax fa 80-200mm 2.8 for an ok price. I will be using this lens on a k10d and understand that with the 1.5x apc sensor the lens will become a 120-300mm. I am planning on getting my hands on the new da* 50-135mm 2.8 when it finally arrives.

I am finding converting from traditional to digital alittle confusing and would love some clarification on something...

My question: if i was to purchase the fa 80-200mm and the da 50-135mm after converting them to the same range would i be duplicating my focal range (both roughly 80-200mm) or would i be having a good cross over in range (50-135mm and a 120-300mm)?

any help is much appriciated

[and]

Simply, always multiply by 1.5x

50-135 = 75-202
80-200 = 120-300

[and]

..And on the question of overlap, I dont think there is a point in having both of those zooms in terms of focal length. if you have the 80-200 then the 50-135 will just give you additional cover of the 50-80 and in that range you can just get an FA 50 instead.

So in terms of focal length I would just get the 80-200 and an fa 50.

of course there are other considerations, SDM, weather sealing, weight. And you can consider those yourself and decide if its worth having such a big overlap.

Alternatively, you could get just the 50-135 and then add a 200mm f2.8 prime.

[Chako]

There are a lot of choices open to you.

For example, you could get a 16-45 F4 for the short end, and that would go well with either lens. I don't think you would notice the few missing focal lengths in daily use. Likewise, you could also get something longer later one.

[roscot]

[quote=mrsnoogle;82481]hey there....
I have been offered a pentax fa 80-200mm 2.8 for an ok price. /quote]

Quite simply, if you can purchase a good example of a FA* 80-200 for under US$2000, than snap it up. It is one of the 2 or 3 best lenses of that focal range built by anyone. If you decide against it, please PM me with the details of the sale, as I would dearly love to own one.

As to your question regarding focal length. It does not change on a reduced size sensor. The field of view is smaller, but 50mm is still 50mm. The DA lenses just have a reduced image circle, so they do not work with film. You can directly compare the ranges of both the 50-135 and the 80-200.