Rusty's Ramble #5: 24mm... My forgotten focal length no more!

 

Anyone who has visited my on-line gallery will see that I shoot a lot of wide landscapes. I use a 1DsII (full-frame sensor) and 17-40 f4 L lens that may as well be glued at 17mm. (Note: 17mm on a full-frame sensor is about equal to using 10-11mm on an smaller APS-C sensor camera like a 40D)

17mm gives a very wide FOV (field of view) which is great, but this often comes at the cost or corner sharpness and wide field distortion at the extremities. I use techniques to minimise the effects of these, such as vertical composition, close foreground objects and hyperfocal focusing to maximise the DOF (depth of field). But get these even slightly wrong, as you will pay the price of soft corners and/or unnatural looking distortion.

Naturally some lenses are better than others, but in general, ALL ultra-wide lenses have these issues to some extent. The Holy Grail for me, has for some time now, been an ultra-wide lens with sharp corners and no distortion..... sadly, my quest continues. 

I should say that my 17-40 is mighty fine lens, as is Nikons latest ultra-wide zoom, but even with the better examples of these lenses offering sharp corners at short focal lengths, the wide-field distortion is pretty much inherent in the FOV. :-( (Note the 17mm image above and how the rocks seem to rush away in the bottom left corner)

Recently I was revisiting my wide landscape work and preparing to once again ramp up my quest for the Holy Grail, when my brain finally kicked into gear..... "Why shoot 17mm all the time anyway?"

.....Der!!!! It was a boom-shanka moment for my tiny pea brain and I reached into my bag for my Olympus 24mm.

I regularly use my Oly 24, but always reserved it for stitched panoramas. When used in vertical/portrait orientation, the 24mm FOV provides just the right amount of image for a single row pano and it's exceptionally sharp, minimal distortion characteristics made it perfect for stitching multiple images. Hmmmm? "exceptionally sharp, minimal distortion characteristics".... der! I should have been shooting some of my regular landscape work with this lens much sooner.

So into my bag went the 17-40 and there it stayed while I gave the Oly 24 a solid run for the weekend. Well the results speak for themselves, sharp contrasty images from corner to corner and no unnatural looking distortion. (as shown)

So why have I done everything at 17mm until now? To be honest I don't really know. In my film days my widest was a Canon EF24/2.8 and back then I always considered it wide enough. After getting the 17-40 for my digital, the ultra-wide FOV became a bit of a novelty that soon turned into standard practice.. I guess I simply got "stuck in a rut" so to speak.

So this begs the question.... is 24mm the new "novelty" for me at the moment? ....I don't think so. I am a bit of a pixel-peeper and image quality is an obsession of mine, so I don't see how sharp corners and no distortion can ever be anything other than "getting it right".

I will still shoot with the 17-40, but it will be no longer automatic to grab it for anything landscape. If the subject matter really needs 17mm (and wide-field distortion and corner softness can be kept to a minimum), then the 17-40 will get a run, but even so.... if that same image can be created equally effectively at 24mm, then image quality will most likely be my deciding factor and it will be the Olympus that I reach for.

I guess all this means that we should be careful not to get set in our ways (as I was).  Every image is new and deserves our attention to every detail, rather than us simply "shooting how we normally shoot".

Cheers

Russell
My Gallery: http://www.pixelpix.com.au/gallery
Australian Digital Photo Of The Day: http://www.potd.com.au


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