[c.a.m]

Is there a way to calculate what the AoV would be from FF to APS-C?

Rather than plugging numbers into a formula, I usually refer to one of the handy-dandy online calculators: Depth of Field (DoF), Angle of View, and Equivalent Lens Calculator ? Points in Focus Photography

For a given lens focal length, the AOV on a full-frame camera will be 1.5 times wider than the AOV on an APS-C camera, which accounts for the so-called 'crop factor' between the two formats.

For example, at a FL of 210mm, the horizontal AOV would be:

• Full frame: 9.8 degrees
• APS-C: 6.5 degrees ( = 9.8/1.5)

- Craig

[Bcrary3]

Rather than plugging numbers into a formula, I usually refer to one of the handy-dandy online calculators: Depth of Field (DoF), Angle of View, and Equivalent Lens Calculator ? Points in Focus Photography

For a given lens focal length, the AOV on a full-frame camera will be 1.5 times wider than the AOV on an APS-C camera, which accounts for the so-called 'crop factor' between the two formats.

For example, at a FL of 210mm, the horizontal AOV would be:

• Full frame: 9.8 degrees
• APS-C: 6.5 degrees ( = 9.8/1.5)

- Craig

So, if I am following correctly, the FA* 70-200 would have an AoV (on an APSC sensor camera) of 23 degrees to 8.4 degrees and the 50-135 would retain the same AoV of 31.5 to 11.9.

The 70-200 would appear approximately the same on the APSC as a 105-300 on FF if any of this makes sense. lol

Without having access to try either of them makes getting ready to shell out some $$ a much more involved process.

[c.a.m]

So, if I am following correctly, the FA* 70-200 would have an AoV (on an APSC sensor camera) of 23 degrees to 8.4 degrees and the 50-135 would retain the same AoV of 31.5 to 11.9.

Yes, I believe that's correct -- for a diagonal AOV.

The 70-200 would appear approximately the same on the APSC as a 105-300 on FF if any of this makes sense. lol

Makes perfect sense when talking about the AOV. You've stated it clearly, I think.

Without having access to try either of them makes getting ready to shell out some $$ a much more involved process.

Yeah, that's a challenge for many of us when few brick-and-mortar stores carry Pentax gear. I might suggest that the lens reviews here on Pentax Forums provide useful user reports, including comments on handling, size, weight, etc.

Personally, I was dissuaded from the DFA* 70-200 when I had a chance to handle it and a K-1 at a trade show a couple of years ago. I found that its weight and size exceeded my comfort threshold. On the other hand, there are plenty of users who don't mind the weight and are happy to carry it for the high optical quality. I guess I'm just a scrawny Canadian, despite having shoveled tons of snow over the years.

- Craig

[clackers]

So my only thing with the FA 70-210 is that these are intended for the FF (AFAIK) which would effectively put the focal range around 105-315 that is the only thing, but I supposed that I could supplement that focal range with something else. (typically used the DA Limited 20-40, Sigma DG 50mm 1.4) Want to keep my kit as light as possible, also would prefer something a bit faster than f4 but gotta take what we can get lol.

I think you're a little confused here, Bcrary.

You say now you prefer faster than f4 but the DA*60-250 you were asking us about is f4!

And it does not matter if a lens was designed for FF, it will still work an APS-C, as the glorious FA Limiteds demonstrate.

And you say that the focal length range of the 70-210 is problematic but I read in one of your posts you're considering the FA*70-200.

I don't understand!