[Leica] Picture taking technique

[Erwin Puts <imxputs@ision.nl>]

"brougham3@yahoo.com" (I am sorry that I cannot address you by your 
first name as it is not stated)
asked in part:
> So what's wrong with a visual inspection, then?  If you can't see any
> degradation, does it matter if it is present?  From a practical 
> standpoint,
> what's it matter if the theoretical limit is 100 lp/mm for a 
> photographer
> who hand-holds 95% of the time?
>
> I ask because I seek your expert opinion, Erwin.  I'm genuinely curious.
> Does the defocus problem only really matter if you're using a tripod, 
> slow
> film, and trying to get close to the theoretical maximum?  If hand 
> holding
> already degrades the image, how important does the mismatch between 
> Leica
> lenses and Hexar bodies become?

I am searching for a way to express my thinking that is clear and 
consistent. What I tried to say here is this.
With careful technique you can extract maybe 80% of the potential image 
qualities of a film/lens/body combination. With a technique that 
necessarily introduces severe image degradation  (defocus, hand held 
shooting below 1/250), your results will by default much lower.
When you use equipment that has its own sources of degradation (large 
tolerances, engineering mismatch between components) you will also 
automatically get a degraded image (that is compared to the one you 
could produce when all components are spot on).

 From a practical point of view it seems indeed irrelevant which sources 
cause the degradation. In both cases you get at best 30% of the feasible 
image quality.
And if you are happy with the resultant quality, you are right not to 
worry what is the cause of the trouble, as you do not seem to have any 
concern at all. You like what you get, irrespective of what you might 
get if degrading factors are excluded.

My point is that there is a vast and significant difference between the 
use of  the method of visual inspection in order to settle the question 
whether a photographer is satisfied with the result and the use of this 
method to settle the question what is the best image quality attainable.
If you are only interested  in creating pictures you personally like and 
are comfortable  with, the method of of subjective assessment (or visual 
inspection) is perfectly viable and sound.

If you are interested in getting the best possible results with your 
equipment and want to know how to handle the many factors that do 
degrade the image, you need a method that can identify the possible 
sources of image degradation and a strategy how to cope with this.

It is for this approach that it is of paramount importance to 
distinguish between user induced defocus errors and manufacturing 
induced  defocus errors.
You cannot dismiss this difference by claiming that the result might be 
identical. In the first case I can do something about it, in the second 
case I am lost.

And I am sure it is of interest to users to know what does cause the 
image degradation. In some situations it may be irrelevant as you have 
no options or do not care about improvements.

But if you wish to improve your image quality, it does matter.

It may be true that when taking pictures at 1/30 any defocus erors will 
hide behind the degradation induced by movement degradation. Or the 
other way around. But if I know it is an error of movement, I can 
improve the result.
To give a direct answer to your last question: the defocus error 
(mismatch Leica lens/ Hexar body) is an error that is constant. It will 
be more of a problem if the shutter speed and the speed of the 
filmemulsion get faster. Even without a tripod I can get quite vibration 
free (satisfactory)  pictures at 1/250 or when using flash, but the 
defocus error will have a significant impact. At least at the wider 
apertures.
THis is the old trade-off: use a slow shutter speed and a lens well 
stopped down and you cover up focus problems and generate vibration 
problems. Use a higher speed and a wider aperture and you need accurate 
focussing and a well corrected lens.
Any photographer has to specify his/her personal trade off in relation 
to his/her demands on pictorial quality. In my view (and that is why I 
choose Leica products) this choice/demands should not be limited by 
issues of limitations induced by equipment performance.
But is perfectly reasonable to match your  requirements to what the 
equipment is able to deliver.


Erwin