Bruce wrote:
"mj" wrote:
For better than 20 years I serviced both 35mm and most medium format
systems. I can say that in a small percentage of all the lenses I have
repaired (less then 20%) I have seen "protection" filters break into the
front element of the lens scratching it. Hoods generally offer better impact
protection. IMO


How much protection does a hood offer against damaging the front
element of the lens through careless cleaning?

A filter is extremely easy to clean. You can even take it off the
lens to clean it. If you scratch or damage a filter, it is quick and
relatively cheap to replace. Try doing that with the front element of
a good quality lens, and you will be faced with a very large bill.

Just dab some india ink into the scratch and put the filter back on the
lens. I have filters going well over $100. I'm not throwing them out!

[Of course you could always sell it on eBay, claiming that the
defective front element did not affect the quality of the images
produced ... funny how many lenses on eBay are thus described!]

With film, the often alleged optical degradation through using a
filter was a non-issue as long as good quality multi-coated filters
were used. However, things have changed a little with digital because
of the greater reflectivity of the digital sensor. Whether the latest
filter coatings have made this a non-issue once again is a moot point.

I've seen a scant few examples of this effect and the promotion of the
idea seems to be bread and butter of Sigma to promote their 'digital'
lenses.


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