Three new Nikkors officially annouced

[jhinkey]

Nobody wants to address my question as to whether or not folks are blocking the VF when stretching out for these fish eye images.   

No, only for long exposures do I block the viewfinder with the built-in shutter on my D800.

J

[CS]

Normal precautions, not unique to any particular lens type:
Block it you are relying on the camera meter to control exposure, unless it's dark outside.  If you aren't on auto exposure, it doesn't matter whether you block it or not, except if there is a possibility that extremely bright light(direct sun, bright spotlight, laser, etc) could enter the finder and find its way into the image path between the lens and sensor. On most occasions outside during the day, it isn't necessary to close the finder.

Now we are getting somewhere.

I know isn't specific to a lens type, but in order not to include feet, etc, with a fisheye, it will have to be extended out from the shooters body, which leaves the VF not protected by the shooters head blocking extraneous light. So, let it go, as in ignore it, or block the VF from interfering with the exposure. You understood my question, Keith, thanks.

Yes, auto would compensate, if it was used.

[CS]

No, only for long exposures do I block the viewfinder with the built-in shutter on my D800.

J

Okay, only for long exposures, thanks.

[David H. Hartman]

As a rule I block the viewfinder if using Aperture Preferred or any auto exposure mode if the camera isn't to my eye. If I set the camera down where the sun shines on the viewfinder eyepiece I also close the blind (D800 or D300s).

Dave

In days of old CdS light meters could go blind, temporarally or permanently if exposed to direct sunlight for too long. They also had a memory of bright light to deal with. Maybe I too carful from habit? Maybe not?

[Roland Vink]

Done...

Thanks - already loaded to my site

[Roland Vink]

Sigma clearly states that they use the equisolid angle projection method for their circular fisheyes for FX and DX, and 10mm diagonal fisheye for DX.  There is no mention of the projection method for the FX 15mm, but it should be safe to assume that its projection method is the same as that for the others.

The rectlinear fisheye Nikkors use equidistant projection method.

To my eyes, the exaggeration of the central area is stronger on the Nikkor primes.  But the new fisheye zoom at 15mm, the central area seems to be less exaggerated.

The early Nikon 8/8, 7.5/5.6 and 8/2.8 fisheyes use equidistant projection, or very close to it. From memory, the tables that Nikon published show slightly higher distortion towards the edges but it is minor.

I don't remember seeing anything which states the projection used for the 16/3.5 and 16/2.8 lenses. Since the 16/3.5 had only 170° field of view compared to 180° for the 16/2.8, the projections must be different. A full frame equidistant fisheye with 180° field of view from corner to corner should have a focal length close to 14mm. The Nikon 16mm fisheyes exaggerate the central portion more with greater compression and higher distortion towards the edges, so the projection might be closer to equisolid. I'm not sure if any effort was made to conform to any specific projection though, maybe they were designed to whatever was easiest! The new fisheye zoom at 15mm probably has a projection closer to equidistant.

[Akira]

I noticed that the new zoom fisheye employs the equisolid angle projection method instead of Nikon's conventional equidistance projection method.  (Apparently the projection method is mentioned only in Nikon's Japanese website.)

Now my question about the shortened focal length is solved. 

Roland, I've found the answer. 

[Asle F]

Nobody wants to address my question as to whether or not folks are blocking the VF when stretching out for these fish eye images.   

I use to block the viewfinder when not looking through it.
But when hand holding a fisheye and don't want my feet in the picture, I do look through the viewfinder. Using live view and stretched arms does not give me the control I want.

[CS]

I use to block the viewfinder when not looking through it.
But when hand holding a fisheye and don't want my feet in the picture, I do look through the viewfinder. Using live view and stretched arms does not give me the control I want.

Very understandable, thanks for your response. Asle.

[Roland Vink]

Just curious, what is the hood for the 8-15mm fisheye for? Obviously can't be used on FX if a circular image is required

[Akira]

Just curious, what is the hood for the 8-15mm fisheye for? Obviously can't be used on FX if a circular image is required

The dedicated hood and cap are designed to be removed altogether.  I guess that they are to be removed altogether when you use the lens as FX circular fisheye.