From: JimKramer on
"Troy Piggins" <usenet-0912(a)> wrote in message
>* JimKramer wrote :
>> "Calvin Sambrook" <csambrook(a)> wrote in message
>> news:hg3u0c$317$1(a)
>> [---=| Quote block shrinked by t-prot: 7 lines snipped |=---]
>>> shorter focal length will look different. Distances will be compressed
>>> for a start and foreground objects will appear relatively smaller. Not
>>> the same thing at all. I'm very surprised to hear that from you Alan,
>>> you
>>> seem to be a very "technical" photographer.
>> Calvin you are mistaken. Unless you use a lens that disproportionately
>> alters the field of view, i.e. fisheye or really bad barrel distortion,
>> there will be no difference as long as the same F stop is used. I
>> encourage
>> you to try it with a zoom lens on a tripod.
> I kind of agree with Calvin. The perspectives are different.
> If you shoot a scene with a 100mm lens, then crop it down, and
> compare that with a shot taken with a 35mm lens, they will look
> different because you are taking the photo from a different
> location, so the perspectives are different. No?

No, same location, different FoV, from different lenses, cropped to be the
same FoV. Perspective doesn't change from the same location, check Alan�s
original post.

Now you are also going the wrong way as you would crop the 35mm shot down to
what the 100mm shot would be.

As soon as you start physically moving around, then all bets are off,
because perspective will change.

If what you meant to say was take a shot with a 100mm and then move closer
to repeat the shot with a 35mm lens so that the focal plane encompasses the
same field of view: then you would have two significantly different images,
because of the perspective differences. But that's not cropping. :-)


From: David J Taylor on
Could you keep these postings in one newsgroup rather than three, please?

From: Bowser on

"Michael Benveniste" <mhb(a)> wrote in message
> On Sun, 13 Dec 2009 14:41:52 -0500, Bowser <Canon(a)Nikon.Panny> wrote:
>>Damn shame. According to Big Bob's angle of view calculator, they
>>should be 46.8:
> And that's correct, _if_ most nominal 50mm lenses were actually 50mm.
> But they aren't for reasons dating back to the rangefinder era.
>>I strongly suggest you dump all the sub-standard gear, get a 5D II
>>along with a 50mm 1.4 Canon lens and then you can enter the
> I doubt it would help. It's actually because of Canon (and indirectly
> Leica) that Nikon's 50mm lenses are designed to have a focal length of
> 51.6mm.
> Of course, had Nikon done it "right," their 50mm lenses would have had
> a focal length of 52.3mm to match that of Contax/Zeiss.

I had no idea this mandate could be so complicated.

>>OK, how about 46.8 degrees plus or minus 5 degrees?
> 3 digit precision +/- 10 percent. Sounds about right. That may even
> cover the shift in focal length with focus distance found in most
> modern lenses...

Damned modern lenses.

From: Bowser on

"Bruce" <docnews2011(a)> wrote in message
> On Sun, 13 Dec 2009 11:46:27 -0800, Paul Furman <>
> wrote:
>>I'm tempted to cheat this mandate by using a 50mm reversed on bellows
>>for a macro shot <g> but I won't.
> As a *photographer* you ought to know that the bellows extension would
> mean that the field of view was very much less than 46.8 degrees.

He knew, and was joking. You know nothing, and submit nothing. Why? Why not
show us all how amazing you are the show us some of you work?

Oh, wait. I know why.

From: Bowser on

"Troy Piggins" <usenet-0912(a)> wrote in message
> * Robert Coe wrote :
>> On Mon, 14 Dec 2009 07:28:43 +1000, Troy Piggins <usenet-0912(a)>
>> wrote:
>>: * tony cooper wrote :
>>: > On Sun, 13 Dec 2009 11:44:50 -0500, Bowser <Canon(a)Nikon.Panny> wrote:
>>: >
>>: >>OK, here's the new mandate for the Shoot In, due January 17th, 2010.
>>: >>Let's simplify things this month. Drag out those 50mm primes and shoot
>>: >>a pic using nothing but that, or whatever lens you have that provides
>>: >>the equivilant angle of view of, yes, 46.8 degrees. Use a zoom if you
>>: >>like, but lock it at "50." Fire at will...
>>: >>
>>: >>
>>: >>
>>: >>
>>: >
>>: > I don't understand. I had prime lenses when I was shooting film, but
>>: > all I have now are zoom lenses including an 18/55. Does that mean I
>>: > shoot at 50?
>>: >
>>: > Does it mean no cropping? Just resizing?
>>: Yeah mate, challenge yourself. As Bowser said, lock the zoom at
>>: 50 (or crop equiv) and no cropping. :)
>> I don't believe he said no cropping.
> Okay, but what's the point of shooting at "46.8 degrees" if
> you're then going to crop it to some other field of view? If you
> have a crop sensor, shoot with a wider lens so the equivalent
> field of view you end up with is 46.8 deg or thereabouts.
> Anyway, your interpretation is up to you. Sorry.

the final shot submitted should be around 46.8 deg. Shoot with a 14mm lens
if you like, but crop it to the center portion equivilant to a 50mm lens on
a FF body.