Center filter needed for Grandagon-N 90 4.5?

[Ben Chase]

While I primarily shoot landscapes, I'm planning on starting to shoot some architecture, and I'm wondering about what my limitations are with this lens and light fall-off. I shoot transparency film (Provia 100F and Velvia 100).

B&H has the center filter for this lens listed at $576 - kind of a ridiculous price for a piece of glass. I'm just wondering what the experiences of others have been that have used this lens for these types of applications.

Thanks,

Ben C

[Brian Vuillemenot]

Shoot some film and see how you like it. I'm guessing you won't need (or want) the center filter with a 90. I often shoot transparency film using a 75 without a center filter. The fall off is really not that noticable in many cases, and the slight darkening in the corners can be a nice effect.

[Brian Vuillemenot]

Oh, by the way, you can buy a Heliopan center filter for quite a bit less than the Rodenstock if you decide to go that way.

[Frank Petronio]

Take a can of matte black spray Krylon and position it precisely 24 inches away with the nozzle centered on the front element. A quick one fingered burst should do the trick and save you hundreds of dollars.

Just try shooting with it for a while. If you're doing architecture and have large smooth areas that need to be evenly lit, it probably makes sense to get a CF. But for landscape and general shooting you may even prefer the subtle darkening at the edges.

[Bob Salomon]

Shoot first and see if you need it but remember to use the maximum amount of movement that you think you will need with a 90mm. Remeber that while the fall off is pretty symetrical when not using movements you can easily accentuate the fall off when you do use movements.

Also a center filter will not work until the lens is stopped down at least 2 stops. Use the lens at less then 2 stops down and the center filter's effect vanishes.

[Brian Vuillemenot]

Frank, are you serious about spray painting the front element? Wouldn't it make more sense to spray paint a cheap UV filter for a bargain home made center filter?

[Leonard Evens]

I have the 90 mm f/6.8 Grandagon-N. I often need to use a center filter for architectural subjects. First of all, such subjects often require significant rise, which means you are going to approach the limits of the image circle. Secondly, for color, the fall-off may vary by primary color which leads to subtle color shifts over the field. I've noticed this particularly when photographing white or gray building facades.

[Ben Chase]

Thanks guys, I'll see how it goes!

[Ben Chase]

Oh, one other thing...why is the front filter thread on center filters so large? Both the Rodenstock and the Heliopan are over 100mm... Why can't I just get a center filter that just looks like a normal filter?

It pretty much blows away any possibility of me using an additional filter like an ND grad if I'm shooting landscapes. All my singh-ray grad filters are of the P-mount variety.

[Bob Salomon]

Oh, one other thing...why is the front filter thread on center filters so large? Both the Rodenstock and the Heliopan are over 100mm... Why can't I just get a center filter that just looks like a normal filter?

It pretty much blows away any possibility of me using an additional filter like an ND grad if I'm shooting landscapes. All my singh-ray grad filters are of the P-mount variety.

Because the wider front on wide angle filters is what eliminates vignetting. It is very easy to use filters with a center filter. In this case you either use 100mm filters or a 100 to 105mm step up ring (Heliopan makes both) and add them to the front of the center filter.

[Frank Petronio]

Brian - you should know me by now. I paint all my lenses with Krylon.

[Ben Chase]

Because the wider front on wide angle filters is what eliminates vignetting. It is very easy to use filters with a center filter. In this case you either use 100mm filters or a 100 to 105mm step up ring (Heliopan makes both) and add them to the front of the center filter.

Now if only 100 - 105 filters weren't so bloody expensive... Looks like I'll have to move up to the Lee size if I need filters that big.... Sigh.