Canon drop-in filters

[Dave Hassell]

Sometime ago there was a thread about the effect of filters being used on the front of lens, such as the Canon 100-400mm, and the general opinion was that they are detrimental and should be avoided.

Does anyone have any opinions, or experience, of drop-in filters on the Canon long lenses spoiling the images?

Dave.

[Alfred Forns]

Filter wise I only use ND filters at times and Polarizers. The UV filters should be avoided, another glass surface to give you trouble. btw protection wise, I have never scratched a front element and if you do they are not expensive to replace. I believe the front hood of a 500 is more expensive than the front element !!

.. one other filter I have for the 100-400 is the 500D, a close up filter.

If you use drop ins make sure to get the right kind so it fits in the holder and use separate holders, takes too long changing filters !!

[Dave Hassell]

Thanks Alfred. I am aware of the problems with the filters on the front of the lens and I was asking if the same problems could exist with drop-in filters. They are, after all, another piece of glass between the subject and the sensor and could potentially cause the same problem.

Dave.

[Robert Amoruso]

Dave,

I use ND filters with the drop-in on my Canon 600mm to allow me to do pan blurs in the daylight w/o going to f/45. I have not found them to degrade the IQ, but then again it was a blur. If you purchase a HQ filter that is multi-coated, you will lessen image degradation.

[Barry Fisher]

Hi Dave.

You do not appear to understand the way these drop-in filters work. You are not adding another piece of glass to the optical system at all. What you are actually doing is to replace the plain glass filter that is always present on these long lenses with the chosen filter of your choice. eg polariser etc.

When these lenses are supplied by Canon, the instructions specify that they should always be used with a filter in place at the rear of the lens as the optics of the lens have been computed/corrected on the assumption that this will be the case.

Therefore when you use a drop-in filter you simply pull out the plain glass one that is already in place and substitute it with the chosen filter eg a circular polariser etc. When you have finshed using the chosen filter the plain glass filter is dropped back into the lens. Therefore there is no additional glass added to the system.

Hope this helps

Barry

[Alfred Forns]

Thanks Barry I should have mentioned that and also that glass should be cleaned !!!!

I normally check in the workshops and I'm amazed at the dirt in some of them. A while back at Bosque Artie was complaining of poor focusing and it was the factory drop in filter !!!

[Arthur Morris]

That would be quite accurate :confused: :( :)