Magnification Factors

[Guest]

Archived from groups: alt.photography,rec.photo.digital (More info?)

I'm not sure how to interpret magnification factors. I'm looking into
the possibility of picking up a wide-angle converter lens for my HD
camcorder (URL may wrap):

http://www.sonystyle.com/is-bin/INTERSHOP.enfinity/eCS/Store/en/-/USD/SY_DisplayProductInformation-Start?CategoryName=hid_pr_p_new20accyprod_dcc&ProductSKU=VCLHG0872&TabName=comp&var2=

It says that it has a magnification factor of 0.8, and they want $500
for it, although I have a special coupon to get it from $400. But
doesn't seem like 0.8 would be much of a change from the 1.0 of the lens
itself - not much for $500 or even $400.

However, I'm not sure that I know how to interpret that 0.8 number. Is
that a multiplier on the focal length? Does it mean that, if I were
taking a picture of a ruler and the width of the image reads as 1.0
units on the ruler, that with this adaptor, it would read 1.25 (1/0.8)
units?

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buried in spam.)

 

[Jim]

Archived from groups: alt.photography,rec.photo.digital (More info?)

"Gary Morrison" <mr88cet@texas.net> wrote in message
news:lYrme.23385$6g3.3938@tornado.texas.rr.com...
> I'm not sure how to interpret magnification factors. I'm looking into
> the possibility of picking up a wide-angle converter lens for my HD
> camcorder (URL may wrap):
>
>
http://www.sonystyle.com/is-bin/INTERSHOP.enfinity/eCS/Store/en/-/USD/SY_DisplayProductInformation-Start?CategoryName=hid_pr_p_new20accyprod_dcc&ProductSKU=VCLHG0872&TabName=comp&var2=
>
> It says that it has a magnification factor of 0.8, and they want $500
> for it, although I have a special coupon to get it from $400. But
> doesn't seem like 0.8 would be much of a change from the 1.0 of the lens
> itself - not much for $500 or even $400.
>
> However, I'm not sure that I know how to interpret that 0.8 number. Is
> that a multiplier on the focal length? Does it mean that, if I were
> taking a picture of a ruler and the width of the image reads as 1.0
> units on the ruler, that with this adaptor, it would read 1.25 (1/0.8)
> units?
The 0.8 factor means that the adapter reduces the focal length of the lens
to 80% of its native value. As for your example, no that is not how it
works. These devices are about the only way to get a significantly wide
angle. 80% makes a lot of difference in the appearance of the image.
Jim

 

[Guest]

Archived from groups: alt.photography,rec.photo.digital (More info?)

>>However, I'm not sure that I know how to interpret that 0.8 number. Is
>>that a multiplier on the focal length? ...
> The 0.8 factor means that the adapter reduces the focal length of the lens
> to 80% of its native value.

OK, I'll ponder it in that light. For example, in 35mm-camera terms,
wherein a "normal" lens is about 50mm, it would produce the effect of a
40mm lens.

--

(Preferably reply to the newsgroup, please. If you reply by Email, I
will sincerely try to receive your message, but it will probably get
buried in spam.)

 

[Jim]

Archived from groups: alt.photography,rec.photo.digital (More info?)

"Gary Morrison" <mr88cet@texas.net> wrote in message
news:b%ume.8070$PR6.7736@tornado.texas.rr.com...
> >>However, I'm not sure that I know how to interpret that 0.8 number. Is
> >>that a multiplier on the focal length? ...
> > The 0.8 factor means that the adapter reduces the focal length of the
lens
> > to 80% of its native value.
>
> OK, I'll ponder it in that light. For example, in 35mm-camera terms,
> wherein a "normal" lens is about 50mm, it would produce the effect of a
> 40mm lens.
Yes, but in that case, the difference would not be great. However, if you
install the 0.8 adapter on a lens with a 35mm focal length, the difference
would be much greater.
Jim.)