Sometimes it takes a while to learn the lesson. Don't be me...

I am currently doing some deep trawling of the archives looking for workable items I walked away from.

When I saw this I thought this might illustrate a few worthwhile ideas to share. Now this image was shot on a great outing with a good friend and very very competent fellow photographer. As you can see, the sky was not wonderful but we were blessed to get the setting sun peeking through on the horizon.

At the time, January 2013, I had just had my first 5D III for a few months and also my 21mm Zeiss lens. I thought things could not get better. Oh boy...

Now the first tip - Tip #1 - I wish to share is ALWAYS to keep your original off-camera raw files and not only the subsequent saves. It could be a .psd or a layered Tiff. Doesn't matter, keep the raw. Editing skills, techniques and preferences change. Be sure to be able to come back to the off-camera image.

Then I learned another lesson and that forms the basis for Tip #2. Diffraction softness.

Now, fair enough, when this image was shot it was quite windy and so movement in the foliage is to be expected and indeed very visible. The rocks not so much though.

Now diffraction softness can get hairy and totally over-the-top on a technical level. Please allow me to share a few thoughts I believe are really all you need to know.

When a lens is stopped down too low, say, f/22 or maybe even f/16 or f/11, light begins to bend and diffract inside the lens before hitting the sensor.

Lenses have resolution limits and sensors have resolution limits. Your great 20-year old lens might not work all that nicely on your next 46Mp or 50Mp camera as it did on your earlier 12Mp camera.

Why? When light diffracts inside the lens before hitting the sensor we get softness. A very high resolution sensor which out-resolves the lens shows this very clearly. The above crop from the image at the top shows quite a bit of lack of sharpness. But it was shot at f/22 on a tripod...that should not be, right? Nope, f/22 WAS exactly the problem here. Some time back I did a basic article on diffraction softness here if you like to read that.

The short version is that my 21mm Zeiss lens is only really workable at apertures from f/2,8 to f/5,6 on sensors over 20Mp. On my 12Mp 5D1 and 16Mp 1Ds MkII it seems fine even at f/22. Sometime soon I will get the 50Mp Canon 5Ds R and I will be testing the idea. Fact is, many will say that f/5,6 is mostly the limit for diffraction softness. Now here is the problem...You often wish to be able to do long exposures. ISO can only go that low and so the obvious solution seems to be to stop down the lens aperture to f/22 or so...often a BAD idea.

Now if you wish to get much more technical I could recommend this site for some brilliant reading about diffraction softness and many other things photographic.

Solution to avoiding diffraction softness you ask?

Well, filters are ultimately the only real option if long exposures are your thing. That could be quite costly so identify the lens you are most likely to use for long exposures and start your purchases there. You would also need to decide between screw-on filters or the big guys that mount on a holder in front of your lens. You would do well to check out this site for great products and advice from top local S.A. landscape photographers who actually sell what they use and use what they sell.

Tip #3 - Be careful with the corners on wide lenses. These proteas are clearly distorted and that is what you get in the corners of very wide lenses. My first wide zoom was the Mk 1 version of Canon's EF 16-35mm f/2,8 L USM. The Mark 2 version of this lens has been around for more than a decade and, when it launched, popular opinion made the Mk 1 the worst lens ever made. I made some lovely images with my well-used second-hand Mk 1 but I have always considered the 16-20mm side of it quite useless for my taste.

There are currently two versions of Canon's 16-35mm lens. The f/2,8 Mk 3 and the f/4. I imagine there would have been some very worthwhile improvements over the years but the basic limitations of very wide zoom lenses will not change dramatically when a new model launches.

Tip #4 - Sun stars

As you can see, the Zeiss 21mm Distagon is no star performer here. This could also, at least in part, have been poor technique on my part. Canon's 16-35mm Mk 2 is said to be very good for crisp sun stars. I have never owned or used one so I can't comment on that. My eye is currently on Canon's EF 17-40 f/4 L USM as soon as play money allows and sun stars will be one of my first tests so watch this space. By the way, if you wish to research a lens I would really recommend this site here.

Another great site where you can dig deep into trustworthy info is this site here.

Tip #5 - Poor editing and post-production

Looking at the dark tops of the hills it is painfully clear that I botched it and botched it badly. Always keep the original off-camera raw for this very reason. A bad approach is rarely turned into a great landing. By keeping the original off-camera raw file you probably stack the odds in your favour by about 100%. I love saving monster-sized tiff files because they have huge amounts of information. Saving a layered tiff balloons the file size dramatically but it does not seem to be any good later in tinkering to try new ideas.

Well, I trust something would have been of use so remember to get out and have fun. It is kind of OK to come home with unusable files as long as we learn from the mistakes and get out there again. We only fail when we stop trying.

Until next time!

Anton