Making sense of the sensor size?

Making sense of the sensor size?

Could somebody please explain the jargon used to denote the sensor size?
I mean numbers like 1/1.7. How does this translate to actual size
(dimensions or area)?

What is the typical size for DSLR?
For ZLR?
For good P&S?

Thanks.

Re: Making sense of the sensor size?

RPS wrote:
> Could somebody please explain the jargon used to denote the sensor
> size? I mean numbers like 1/1.7. How does this translate to actual
> size (dimensions or area)?
>
> What is the typical size for DSLR?
> For ZLR?
> For good P&S?
>
> Thanks.

See:

* w w w .dpreview . com /news/0210/02100402sensorsizes.asp

David

Re: Making sense of the sensor size?

RPS <rps@null.void> writes:
> Could somebody please explain the jargon used to denote the sensor
> size? I mean numbers like 1/1.7. How does this translate to actual
> size (dimensions or area)?

Sensors are often referred to with a "type" designation using imperial
fractions such as 1/1.8" or 2/3" which are larger than the actual
sensor diameters. The type designation harks back to a set of standard
sizes given to TV camera tubes in the 50's. These sizes were typically
1/2", 2/3" etc. The size designation does not define the diagonal of
the sensor area but rather the outer diameter of the long glass
envelope of the tube. Engineers soon discovered that for various
reasons the usable area of this imaging plane was approximately two
thirds of the designated size. This designation has clearly stuck
(although it should have been thrown out long ago). There appears to
be no specific mathematical relationship between the diameter of the
imaging circle and the sensor size, although it is always roughly two
thirds.

Source: * w w w .dpreview . com /learn/?/Glossary/Camera_System/sensor_sizes_01.htm

> What is the typical size for DSLR?

Most widespread is the DX-format (used by Nikon, Pentax and Sony),
which is 23.6 mm x 15.8 mm.

> For ZLR?

2/3", used by Oly E-20 and Minolta DiMAGE 7 is 8.8 mm x 6.6 mm.

> For good P&S?

1/1.8" used by most G-series canon is 7.2 mm x 5.3 mm.

--
- gisle hannemyr [ gisle{at}hannemyr.no - * hannemyr . com /photo/ ]
------------------------------------------------------------------------
Sigma SD10, Kodak DCS 14n, Canon Powershot G5, Olympus 2020Z
------------------------------------------------------------------------

Re: Making sense of the sensor size?

Gisle Hannemyr wrote:
> This designation has clearly stuck
> (although it should have been thrown out long ago).

I suspect the manufacturers are happy for the
size to be obscure, since people
might find the actual sizes disconcerting.

There's nothing to stop manufacturers
putting sensor dimensions in
"normal units" in their brochures, advert
or manuals, and yet they don't.

BugBear

Re: Making sense of the sensor size?

bugbear wrote:
> Gisle Hannemyr wrote:
>> This designation has clearly stuck
>> (although it should have been thrown out long ago).
>
> I suspect the manufacturers are happy for the
> size to be obscure, since people
> might find the actual sizes disconcerting.
>
> There's nothing to stop manufacturers
> putting sensor dimensions in
> "normal units" in their brochures, advert
> or manuals, and yet they don't.
>
> BugBear

I suspect your suspicions are accurate. Attempting juggle sensor size,
zoom range, noise and mp value is something they probably prefer to do
behind closed doors where they can better balance value vs hype.
Dave Cohen

Re: Making sense of the sensor size?

On Wed, 29 Aug 2007 10:28:15 -0500, RPS <rps@null.void> wrote:

>Could somebody please explain the jargon used to denote the sensor size?
>I mean numbers like 1/1.7. How does this translate to actual size
>(dimensions or area)?
>
>What is the typical size for DSLR?
>For ZLR?
>For good P&S?
>
>Thanks.


I'm not familiar with ZLR and P&S's, but for DSLRs, unless the
manufacturer says the sensor is "full frame", they're usually in the
range of the reciprocal of 1.5 to 1.7... meaning they are smaller
than the standard 35mm from film days. You'll also hear of "APS"
size sensors, a size of film also smaller than 35mm.

That should help you some...


Jim

Re: Making sense of the sensor size?



james@jamesphotography_nospam.ca wrote:
> On Wed, 29 Aug 2007 10:28:15 -0500, RPS <rps@null.void> wrote:
>
>
>>Could somebody please explain the jargon used to denote the sensor size?
>>I mean numbers like 1/1.7. How does this translate to actual size
>>(dimensions or area)?
>>
>>What is the typical size for DSLR?
>>For ZLR?
>>For good P&S?
>>
>>Thanks.
>
>
>
> I'm not familiar with ZLR and P&S's, but for DSLRs, unless the
> manufacturer says the sensor is "full frame", they're usually in the
> range of the reciprocal of 1.5 to 1.7... meaning they are smaller
> than the standard 35mm from film days. You'll also hear of "APS"
> size sensors, a size of film also smaller than 35mm.
>
> That should help you some...
>
>
> Jim
>
>


There are technical barriers for making full size (35MM double frame)
sensors and there was a good write up when Leica built a digital M
series camera and the compromises that had to be taken. Unfortunately,
I forgot where I read it...

JT

Re: Making sense of the sensor size?

RPS wrote:

> Could somebody please explain the jargon used to denote the sensor size?
> I mean numbers like 1/1.7. How does this translate to actual size
> (dimensions or area)?

Dpreview has a good info page on this:

* w w w .dpreview . com /news/0210/02100402sensorsizes.asp

>
> What is the typical size for DSLR?

They can be full frame or a 1.6 crop of that.

> For ZLR?

There's really no common agreement on what constitutes
a ZLR, so who knows what the sensor size would be :)

> For good P&S?

They genrally use 1.1/8

Re: Making sense of the sensor size?

RPS <rps@null.void> writes:
> Could somebody please explain the jargon used to denote the sensor
> size? I mean numbers like 1/1.7. How does this translate to actual
> size (dimensions or area)?

Scroll down a bit to figure 1, to see a visual presentation of
various sensor sizes: * hannemyr . com /photo/crop.html .
--
- gisle hannemyr [ gisle{at}hannemyr.no - * hannemyr . com /photo/ ]
------------------------------------------------------------------------
Sigma SD10, Kodak DCS 14n, Canon Powershot G5, Olympus 2020Z
------------------------------------------------------------------------

Re: Making sense of the sensor size?


"RPS" <rps@null.void> wrote in message
news:290820071028155958%rps@null.void...
> Could somebody please explain the jargon used to denote the sensor size?
> I mean numbers like 1/1.7. How does this translate to actual size
> (dimensions or area)?

It actually doesn't translate very well at all, and is a goofy system that
should have been abandoned long ago. The fraction refers to the old video
tube size in inches, which is the way such sensors are traditionally sized
but obviously has nothing to do with digital still cameras.

>
> What is the typical size for DSLR?

Those are not described in that way; only compact cameras use the fractional
inch method. Nikon and some other DSLRs mostly use a sensor of either 23.7 x
15.6 mm or 23.6 x 15.8 mm, in either case roughly the same as the full APS-C
format and often referred to by that term. Most Canon DSLRs s have a
slightly smaller sensor than that, some other makes are smaller still, and a
very few are larger.

> For ZLR?
> For good P&S?

Both of those types use sensors in the fractional inch sizes, though often
the "inch" is omitted and "type" is substituted. So for example one
manufacturer may call a particular sensor "2/3 inch" and another may call
the same sensor "2/3 type."

Whatever it's called, the 2/3 type is the largest sensor generally found in
any digicam. Its actual size is about 6 x 8 mm.

Other common sizes are 1/1.8 and 1/2.5 -- there are several other sizes as
well, but those appear to be the ones most often used today. I have read of
sensors as small as 1/3.2 but have never owned a digicam with that small a
sensor myself.

In high-end compact cameras of the type you call ZLRs, such as the Nikon
Coolpix 8800, the 2/3 type was common. Most of today's superzoom ZLRs use
much smaller sensors than that, however.

For a very good but more compact camera such as the Nikon P5000, the 1/1.8
type is used and is undoubtedly the best choice. Smaller sensors than that
are more likely to give problems with noise at the higher ISOs, all else
being equal. But where extreme compactness is important it's usual to see
sensors of 1/2.5 type or smaller. Also, many of the superzooms today use
1/2.5 type sensors. It is adequate for most ordinary use.

Camcorders of course have much smaller sensors than these.

Neil

Re: Making sense of the sensor size?


"Neil Harrington" <not@home.today> wrote in message
news:pKydnXD2Utxn-kXbnZ2dnUVZ_oimnZ2d@comcast . com ...

>
> Whatever it's called, the 2/3 type is the largest sensor generally found
> in any digicam. Its actual size is about 6 x 8 mm.

Correction, that should be about 6.6 x 8.8 mm.

>
> Neil

Re: Making sense of the sensor size?

Neil Harrington wrote:
>
> Those are not described in that way; only compact cameras use the fractional
> inch method. Nikon and some other DSLRs mostly use a sensor of either 23.7 x
> 15.6 mm or 23.6 x 15.8 mm, in either case roughly the same as the full APS-C
> format and often referred to by that term.
>
> ...
>
> Whatever it's called, the 2/3 type is the largest sensor generally found in
> any digicam. Its actual size is about [6.6] x [8.8] mm.
>
> Other common sizes are 1/1.8 and 1/2.5 -- there are several other sizes as
> well, but those appear to be the ones most often used today.

What are the actual physical dimensions of 1/1.8 and 1/2.5 sensors? Do
DSLR sensors really have more than six times the area of a 2/3 sensor? Wow.

Thanks for the informative article.

--
Dave Sill

Re: Making sense of the sensor size?


"Dave Sill" <dave@sill.org> wrote in message
news:13dgts6lobirrb7@corp.supernews . com ...
> Neil Harrington wrote:
>>
>> Those are not described in that way; only compact cameras use the
>> fractional inch method. Nikon and some other DSLRs mostly use a sensor of
>> either 23.7 x 15.6 mm or 23.6 x 15.8 mm, in either case roughly the same
>> as the full APS-C format and often referred to by that term.
> >
> > ...
> >
>> Whatever it's called, the 2/3 type is the largest sensor generally found
>> in any digicam. Its actual size is about [6.6] x [8.8] mm.
>>
>> Other common sizes are 1/1.8 and 1/2.5 -- there are several other sizes
>> as well, but those appear to be the ones most often used today.
>
> What are the actual physical dimensions of 1/1.8 and 1/2.5 sensors? Do
> DSLR sensors really have more than six times the area of a 2/3 sensor?
> Wow.

Yep. Compact digicam sensors really are tiny compared to DSLR sensors.

The 1/1.8 type is about 5.32 x 7.18 mm, and the 1/2.5 type is 4.29 x 5.76
mm.

You can find the *approximate* size of any sensor if you know the actual
focal length of the camera's lens and its 35mm equivalence, both best taken
at the long end of the zoom for the sake of better accuracy. Dividing the
latter by the former will give you the digicam's lens factor. Dividing the
diagonal of a full 35mm frame (about 43.2 mm) by the lens factor should give
you the diagonal of the digicam's sensor. However, this is a rough method
(because the camera lens's stated focal length may not be precise) and may
not give you exactly the figures above.

More sensor sizes are given here:
* w w w .dpreview . com /learn/?/Glossary/Camera_System/sensor_sizes_01.htm

>
> Thanks for the informative article.

You're very welcome.

Neil

Re: Making sense of the sensor size?


"Neil Harrington" <not@home.today> wrote in message
news:LMqdncyWda8cHEXbnZ2dnUVZ_t6onZ2d@comcast . com ...
>

>
> The 1/1.8 type is about 5.32 x 7.18 mm, and the 1/2.5 type is 4.29 x
> 5.76 mm.
>
> You can find the *approximate* size of any sensor if you know the actual
> focal length of the camera's lens and its 35mm equivalence, both best
> taken at the long end of the zoom for the sake of better accuracy.
> Dividing the latter by the former will give you the digicam's lens factor.
> Dividing the diagonal of a full 35mm frame (about 43.2 mm) by the lens
> factor should give you the diagonal of the digicam's sensor. However, this
> is a rough method (because the camera lens's stated focal length may not
> be precise) and may not give you exactly the figures above.

Expanding on this a little:

Most (but not all) compact digicams have sensors in the 4 : 3 aspect ratio.
This should be convenient for finding the diagonal of the sensor, since it's
the 3-4-5 right triangle familiar if you remember your geometry, i.e. if one
side is 3 units and the adjacent side is 4, the hypotenuse must be 5.

So in the case of the 2/3 type sensor used in my Coolpix 8800 for example,
the 6.6 x 8.8 mm sensor has a diagonal of just 11 mm. A full 35mm frame (24
x 36 mm) has a diagonal of about 43.2 mm, so the lens factor is 43.2 / 11 =
3.927. . . , and multiplying this by the lens's marked focal length (at the
long end) of 89mm, the 35mm equivalence works out to about 349.5mm. This is
close enough to the stated f.l. of 350mm at the long end. This is really
just doing the same math suggested in my previous post, only backwards.

The aspect ratios are different of course, the full-frame 35 being 3 : 2
while the digicam's is 4 : 3. But this doesn't really matter; it's always
the format diagonal that's used in calculations of 35mm equivalence.

Neil

Re: Making sense of the sensor size?

Neil Harrington wrote:
> "RPS" <rps@null.void> wrote in message
> news:290820071028155958%rps@null.void...
>> Could somebody please explain the jargon used to denote the sensor size?
>> I mean numbers like 1/1.7. How does this translate to actual size
>> (dimensions or area)?
>
> It actually doesn't translate very well at all, and is a goofy system that
> should have been abandoned long ago. The fraction refers to the old video
> tube size in inches, which is the way such sensors are traditionally sized
> but obviously has nothing to do with digital still cameras.
>
>> What is the typical size for DSLR?
>
> Those are not described in that way; only compact cameras use the fractional
> inch method. Nikon and some other DSLRs mostly use a sensor of either 23.7 x
> 15.6 mm or 23.6 x 15.8 mm, in either case roughly the same as the full APS-C
> format and often referred to by that term. Most Canon DSLRs s have a
> slightly smaller sensor than that, some other makes are smaller still, and a
> very few are larger.
>
>> For ZLR?
>> For good P&S?
>
> Both of those types use sensors in the fractional inch sizes, though often
> the "inch" is omitted and "type" is substituted. So for example one
> manufacturer may call a particular sensor "2/3 inch" and another may call
> the same sensor "2/3 type."
>
> Whatever it's called, the 2/3 type is the largest sensor generally found in
> any digicam. Its actual size is about 6 x 8 mm.
>
> Other common sizes are 1/1.8 and 1/2.5 -- there are several other sizes as
> well, but those appear to be the ones most often used today. I have read of
> sensors as small as 1/3.2 but have never owned a digicam with that small a
> sensor myself.
>
> In high-end compact cameras of the type you call ZLRs, such as the Nikon
> Coolpix 8800, the 2/3 type was common. Most of today's superzoom ZLRs use
> much smaller sensors than that, however.
>
> For a very good but more compact camera such as the Nikon P5000, the 1/1.8
> type is used and is undoubtedly the best choice. Smaller sensors than that
> are more likely to give problems with noise at the higher ISOs, all else
> being equal. But where extreme compactness is important it's usual to see
> sensors of 1/2.5 type or smaller. Also, many of the superzooms today use
> 1/2.5 type sensors. It is adequate for most ordinary use.
>
> Camcorders of course have much smaller sensors than these.
>
> Neil
>
>
Wouldn't the whole thing make more sense if manufacturers would just
agree to always state the sensor size in sq. millimeters!!!?