Focus issues - body or lens - general debate

[mike_smith2]

I have been following these "sharpness" postings over the last 6

months. Personally I have come to the conclusion that it is a body

build issue. How many times did people complain of lens softness

with film bodies? - rarely if ever.

 

I have a 1DdsII in for service focus issues at present. All my

telephoto lenses work perfectly on Film and a 1D but front focus in

AF mode on the 1DsII,

 

I suppose that the problem could eminate from two sources;

 

(i) a manufacturing thickness issues of the sensor or the AA filter

producing focal plane variation or build mounting of sensor issues,

 

(ii)an increase in resolving power of the new generation digital

bodies showing up lens problems hetherto not noticed

 

However you cannot get away from the fact that the traditional

machined film channel and pressure plates used on film bodies suffer

far fewer focus issues than the digital bodies using basically the

same the same AF system and lenses; that is EOS 3 or 1v bodies rarely

suffer focus issues compared to the 1D series.

 

 

Mike Smith

 

UK

[jim_larson1]

I have recently seen posts complaining about banding.

 

The proof provided was JPEG's enlarged 400%.

 

Stuff like that never happened with film.

[chiswick_john]

Digital alows you to see at very high res what your camera and lens are doing. With film this was only possible with either high res scans or large prints and for most people these were never an option so they never saw it. Lenses have focus errors - some of mine do and some don't - they are consistent back or front focus errors and are not resolved by changing bodies - they are lens issues. I have seen body focus errors on a freinds 10D but my 20D and old 300D were very accurate. It's quite easy to place a sensor very accuatley in the right place with moderm manufacturing - it's very basic engineering. It was also very easy to machine film rails to be in the right place as well. What was near impossible was to get film emulsion to lie flat in the right place -it will bulge due to heat, humidity, emulsion type ( which also varied in thickness), where it was on the roll ( end or start) and how long since you wound on. All of these were real issues with film that are not issues with digital. lastly - area for area digital sensors far out resolve film - they are ruthless at exposing lens weaknesses, AF weaknesses and user error.

[yakim_peled1]

<p> <a href="http://www.cps.canon-europe.com/kb/overview.jsp?categoryId=1000">Here</a> are some of Canon's official answers regarding AF. HTH.</p>

 

<p>Happy shooting, <br>

Yakim.</p>

[jon_austin]

Jim Larson: "The proof provided was JPEG's enlarged 400%."

 

Not to mention, Levels set up the wazoo.

[PuppyDigs]

<P><I>"Digital alows you to see at very high res what your camera and lens are doing.

With film this was only possible with either high res scans or large prints and for most

people these were never an option so they never saw it. </I></P>

<P>Oh come on, anyone serious about photography had a collection of loupes. Typically

4x to view the entire chrome or neg, 8 or 10x for detail and sharpness and 25-50x pocket

microscope for grain and small details. Those that did darkroom work focused their

enlarger on the grain using a powerful loupe. I'd say only very causal snapshooters lacked

these tools and probably only made 4 x 6 prints anyway.</P>

[grahams]

Well said, PF - and I know what issues I'm dealing with, not confused by software data processing accuracy, CRT setup, sensor physics, etc.