Lens hood for Pentax 67ii lens?

I'm thinking of getting a rubber collapsible lens hood on ebay for a Pentax 75mm shift lens but when I looked it up, most of people has a rectangular shape hood for their pentax lenses such as this one below.

http://image2.xitek.com/forum/200501/205/20502/20502_1105690088.jpg

My question is would I get some vignetting problem if I get something like this circular one?

http://www.ebay.com/itm/49-52-55-58...er_Accessory_Bundles&var=&hash=item4175757a8b


Thanks,

Rectangular or round, vignetting depends on the diameter of the hood at the corners vs. the angle of view of the lens. The official Pentax 75mm rectangular hood (for a fixed, non-shifting lens) will vignette on a 75mm shift lens if you shift the lens far enough. When using a shift lens on small format cameras, I would eliminate the lens hood, and try to shield light sources from striking the lens.

A rectangular hood, if properly proportioned (i.e. designed specifically for a given lens) will work better than a round hood since you are making a rectangular capture.

if the hood remains on the front of the lens in the same position, I wouldn't call the hood the issue, most likely mechanical(barrel in the way) vignetting is the cause. Not the hood.

If the lens move, but the hood(say attached to the body, not to the lens), then you'd have an issue.

-Dan

If you place a well-fitting hood (one that restricts the lens image circle or image forming light to the boundaries of the film) on a shift lens at "0" or "on-axis", and then shift the lens off-axis, the image on the film will vignette. The only way to avoid vignetting when using a hood on a shift lens is to 1) use a less restrictive hood that allows a larger image circle in the camera, and thus allows the image forming light to exceed the boundaries of the film, or 2) use a compendium hood that can be precisely adjusted after the lens is shifted off-axis. Or 3) just don't use any hood on the shift lens and avoid strong rays of light from striking the lens.