Which is better overall?

[philslizzy]

So which would produce better results?

1: A lens with a front focusing element
2: A lens who's optical block moves in and out
3: One in which an internal element focuses

[Oldhand]

The biggest advantage to IF (internal focusing) is the lack of change to the dimensions of the lens.
This is an advantage in macro work where the lens in focusing gets too close to the subject.
If the front of the lens does not rotate, then this is an advantage in using filters like polarisers and graduated ND filters.
Other than that, I can't see that it makes much difference to the final result either way.
OH

[bernhardas]

Edited

[calvin83]

A lens design and made for a certain application.

[paulhofseth]

For a unit being moved, it cannot avoid being designed for a particular set of "conjugates": plane of object-plane of image.

You will find that some enlarging lenses are listed as !:10, others as 1:4. You will see that the Zeiss\CY 60macro is optimized for 1:10, while one Olympus 80mm bellows performs best at 1:1. This is also why one turns some lenses around in order to get up close.

Someone with deeper knowledge of optics will have to reply on moving elements. I have noticed that some zooms (such as the Leitz 35-70) move an internal element in order to get closer and still does maintain reasonable quality of image. One must assume that this is far better than just providing a longer helix. Some macros also have elements moving in relation to each other when they go closer. Whether they perform better than those designed for the distances involved, I do not know, but those I have used satisfy my medium strict demands.

p.

[Gerald]

[pdccameras]

In the most general of cases, front cell focusing lenses will not usually be as good performers as the other two options you presented.

P.

[Lightshow]