Hello Pascal,
> Here's a question about focal lengths and angle of view of certain
> nikkors. The 85mm/f1.8 AF has an angle of view of 28 degrees whereas
> the 85mm/1.4 MF is only 23 degrees. This information is in Peterson's
> book. I thought the angle of view was determined by the focal length. ??
> Also, the 105mm/2.5 is 19 degrees whereas most other 105mm's are 23
> degrees. Is it a typo or different angle being measured?
The angle of view is determined by the focal length, and the film format
used. For 35mm film (as in your nikon) the angle of view from side to side
and diagonally:
lens side diag
85mm 23.9 28.5
105mm 19.5 23.2
135mm 15.2 18.2
The diagonal angle of view is the one usually stated, and agrees with the
figures in my lens catalogue. I guess there is a typo in Mooses book, or
maybe he is stating the horizontal angle of view??
> I am about to choose between the 105/2.5 and 85/1.8 AF. I would
> like to use the lens to shoot mostly portraits inluding some closeups
> using one of th 3T,4T,5T,6T closeup attachments. Has anyone had
> any experience using one of those lenses along with a closeup lens?
> I'm using a manual camera so autofocus is not really the issue.
I would go for the AIS 105/2.5 for the following reasons:
* By itself the 105/2.5 gives greater magnification (1:7.6) than the AF 85/1.8
(1:9.2)
* Closeup filters give greater magnification when used on longer lenses.
Taking these first two reasons together, you will get greater magnification
when using closeup filters on the 105/2.5. With the 4T I estimate you will
get reproduction between 1:3.3 and 1:2.
* Since you are using a manual camera, you will enjoy using a manual lens
much more - focusing is smoother and has a more positive feel. Unless you
have plans to move up to an AF camera, stay with manual lenses.
* The 105/2.5 has a built-in hood.
* The 105/2.5 has nicer bokeh which is good for wide-aperture portraits.
The background blur of the 105/2.5 is relatively smooth. The 85/1.8 tends to
produce blocky blur and doubling of out-of-focus lines.
Both are very sharp lenses. The 85/1.8 is a stop faster which may be useful
for low low conditions. However, the 105 probably suits your needs better.
Roland
