72XL center filter flare

[Bob Salomon]

"That makes sense Bob, but why not take that into account when designing a lens that everyone knows will be used with a center filter? ""

Because lenses and center filters are not sold 1:1. Many people work around the need or like the result without the filter.

"Using the filter improves the image but why not improve it further? Why not design in center filters for very wide lenses?"

As the Linhof distributor we once asked this question. The answer was that center filters are harder to manufacturer then the front element of the lens itself. More rejected center filters are destroyed then would normally be acceptable. Since some people do no want a center filter and since many do not want to be forced to buy a center filter and since a center filter is far from inexpensive it would simply be a bad policy to force one on everyone. In addition the lens manufactturers like Schneider and Rodenstock offr either a 4.5 or a 5.6 lens. If the Center filter was built in they would then be offering a slower lens design. However their competiton like Nikon and Fuji both of whom do not manufacturer a center filter would then have faster lenses - albeit ones with more fall off. It would be a terrible marketing choice to let a competitors lens be faster because they did not correct their fall off while at the same time being cheaper due to their lack of the correction. As stated above many users do not see the fall off or can correcct it in printing.

[Paul Schilliger]

Speaking of lens design, are the Zeiss Biogon really that good with even illumuination across the field? Of course the trade off is the huge and heavy lens design and high price.

[P. J. Hawke]

Thank you all for your helpful responses.

Paul and Henry, I’m glad to hear that I’m not the only one who’s seen this. Paul, I wondered about the reflective finish as well. As I mentioned, I haven’t seen this with the 67mm Heliopan I use on my 90mm F8.0 Nikon, even with extreme rise applied. That filter does seem to me to be much less reflective than the IVb.

Tom, I’m interested to hear that you haven’t had the problem. This leads me to think that it might have something to do with the degree of rise applied. As I usually shoot architecture, I’m often applying a fair amount of rise, but I’ve seen this flare even when applying only a centimeter or so. Please do experiment with more rise and let me know what you find.

Don, thanks for the Heliopan 95mm filter tip. I didn’t know that it existed. Not many retailers seem to carry it. I’ll keep it in mind as my solution of last resort – needless to say, I’m not too eager to buy another $400 center filter. About a comparison, I’d like to do one, but unfortunately I don’t have a scanner that can deal with 4x5 film at the moment. When I get a hold of one, I’ll contact you for sure.

George, I will definitely contact you about designing a shade. That sounds like my best bet at the moment.

Thanks again to you all for your input.