The headache of lens selection

Hi Ian,

I've been into landscape photography for a lifetime and have wrestled with the same issues.  I think whoever said earlier that you'd identified the issue as being that there is no simple solution was spot on.  You have listed many of the issues we've all come across with tests and reviews very well.

You said you print large, but didn't say how large.  As I read your post, it sounds like you've used a print size you feel should still be within the capacity of the APSC format, but have narrowed it down to lens resolution as the limiting issue.

At least one more problem with tests is that they very often take a photograph of a planar test chart and evaluate how well the lens renders it into an image on the sensor.  That has a value of course, but when it comes to actual subjects, it's rare that we're shooting planar objects unless you're doing a lot of either art or architecture.  Scenes have depth.  Even a WA lens with excellent corner to corner resolution (one that demonstrates excellent test chart performance) won't give you the very sharp corners you're seeking if your composition leaves it stretched to its limits for DOF.  Is there a possibility that you are using sub-optimal apertures and/or pushing the limits of the DOF - ie  reaching the point where you're moving just outside the acceptable circle of confusion?  This will show in the near corners first.

I don't know whether you've ever tried lenses with movements.  In many compositions (though by no means all) movements allow you to escape the tyranny of lens DOF limitations and optimise sharpness.   I used to shoot 4X5 and medium format with lens movements and sold landscapes for calendars.  I left it all behind and moved to a DSLR a long time ago, but I've always regretted the lack of movements.  Somehow photography is incomplete without them.  There's something magic in the Scheimpflug effect and fixed lenses just can't get the same all-over biting sharpness for a large print of the classic near-far landscape.  I know that is not entirely helpful when we're shooting APSC, and Pentax in particular, but it may be worth trying by hiring if you just can't get what you're looking for.  I've met a few people who've left various brands to go Canon for exactly that reason - their suite of TS lenses just 'made it' for them.  If I ever went back into that particular business, that's exactly what I'd do, but it's too expensive an option for what is now a pastime.

Regards, Rod