Any Reiken Focal users ??? a distance question please

Let me add that this guy knows what he is talking about. He posts in the Nature forum over on FM and his work is absolutely top-notch. I mean, insanely good!

There is no downside to doing MFA, but nailing focus is about understanding the environment, good technique and practice.

I've always believed that if I spend 9k on a lens and 6k on a body NO mfa is needed, eh, but say I take a fall, a spill, roll down the mountain
then MFA might be in order.
Now if I use FoCal I can also maintain a database on the MFA; go back in a year, or less depending on how many spills (or simple bumping hard into a wall); so
I have a baseline on the lenses/bodies that are important to me.
In the article I linked too it was mind blowing/eye opening/shocking to read about atmospheric determination; remember when he showed a pic at one point in time
and another after the wind came through the area==it changed everything.
What I took away from it was that sometimes no matter if we do a great job with the exposure/focus/etc. Mother Nature still might screw over the shot.
And it also explained in huge ways why in times past with my little GX8 + Leica 100-400 I get some really tack sharp shots at an effective 800mm and other times not.

MedicineMan4040 wrote in post #18106498
I've always believed that if I spend 9k on a lens and 6k on a body NO mfa is needed, eh, but say I take a fall, a spill, roll down the mountain
then MFA might be in order.
Now if I use FoCal I can also maintain a database on the MFA; go back in a year, or less depending on how many spills (or simple bumping hard into a wall); so
I have a baseline on the lenses/bodies that are important to me.
In the article I linked too it was mind blowing/eye opening/shocking to read about atmospheric determination; remember when he showed a pic at one point in time
and another after the wind came through the area==it changed everything.
What I took away from it was that sometimes no matter if we do a great job with the exposure/focus/etc. Mother Nature still might screw over the shot.
And it also explained in huge ways why in times past with my little GX8 + Leica 100-400 I get some really tack sharp shots at an effective 800mm and other times not.

Actually assuming that you get what you pay for, and with optics that usually is the case, the more you spend on a camera/lens combination, the MORE likely it is that it will require precise calibration to get the most from it, certainly when it comes to PDAF using a separate sensor. Take a basic body, say one of the xxxD/Reble line, and fit a less than average kit zoom to it. Even when perfectly focused it is likely to be a bit soft, and of course the small maximum aperture of the lens will mean that the DoF is not going to be razor thin, so a small amount of misfocus is unlikely to even be noticeable, and in this situation the need for MFA is not there.

On the other hand take a large high resolution sensor, and couple that to say a 400mm f/2.8 or 600mm f/4 lens, with superb resolution, and very narrow DoF, thanks to the relatively huge maximum aperture combined that with the fact that even the best quality manufacturing has to have some tolerances built in to allow for interchangeability of the lenses, means that there is a very good chance that the associated small amount of misfocus will be very visible. So in this situation I actually expect that I will have to provide some level of MFA when swapping lens/body combinations.

When it comes to unwanted atmospheric effects, unfortunately having better quality optics, far from making things better, makes them far more obvious. I have been a competitive rifle shooter for almost as long as I have been a photographer, and regularly shoot at long ranges, distances of 1000 yards and even occasionally 1100 yards. I'm also a NRA (GB) qualified rifle instructor. I have had experience using all quality levels of optics over the years, both rifle scopes, and spotting scopes. When using a spotting scope to assess atmospheric conditions, the better the quality the more you get to see. This is really important when dealing with wind speeds up to about 12 mph, as the way that the heat haze, which is commonly referred to by shooters as Mirage, is the optimum method for reading the speed and direction of the wind. On one training course I was on I had the chance to use the spotting scope of the Chief Wind Coach from several wining GB Teams to the Palma Match (World Long Range Championships shot between 800 and 1000 yards). It was IIRC a Zeiss made scope and I think it cost upwards of £3000, with the eyepiece alone costing an additional £1000. This scope had so much resolving power that you could make out individual blades of grass at 600 yards. On a cold March morning with this scope it was easily possible to read the mirage running on the range. The is at a temperature of less than 10C/50F, when all the other optics being used showed nothing, and we are talking a whole range of qualities, from £20 Chinese made scopes, all the way to £1000 Japanese optics.

As a test of this it would be great to have two 5DSr cameras side by side, one fitted with the 75-300 USM III and the other with the 300 f/2.8, and just take a series of shots with both to just see the difference between the way the two very different quality lenses deal with the atmospheric conditions. I am certain that you would see virtually zero difference between each shot with the 75-300, while the 300 f/2.8 is likely to have significant differences from shot to shot as the air moves.

Alan

PacAce wrote in post #18105346
This is interesting stuff. I had never heard of Reiken FoCal until I saw this thread. I used to adjust the focus offset manually so I'm now considering getting this app. What version of the app to you guys recommend I get? Thanks.

I got the Pro version of Focal as well: also because I needed to calibrate my 300mm with tc. Excellent program.

Thanks for the advice, folks. Since I have the 300mm and the 500mm lenses, I'll go with the Pro version also.