P&S 10x, 15x 18x zooms vs DSLR mm

[Bruce Edwards]

Can someone settle this for me? I don't understand what the correlation between say 10x zoom on a Point and Shoot is when referring to say a Nikon 70-300mm lens.

Which one has the longest reach? And what would the 300mm on the Nikon be equivalent to if using the "numberx" value?

Thanks!

 

[chuxter]

Can someone settle this for me? I don't understand what the
correlation between say 10x zoom on a Point and Shoot is when
referring to say a Nikon 70-300mm lens.

First, this is a very common question.

Which one has the longest reach?

Unfortunately, you didn't give enough information to answer your question.

And what would the 300mm on the
Nikon be equivalent to if using the "numberx" value?

The "10X" is the "Zoom Ratio". The 70-300mm lens has a zoom ration of 300/70 or 4.29:1 (or incorrectly stated as 4.29X). The "experts" around here wish that camera manufacturers would not use that "10X" terminology, as it confuses people...they often think it is a "power" rating like on a pair of binoculars. It isn't!

In order to really compare the two cameras, you need to look beyond the "10X" rating on the P&S and the zoom range on the dSLR.

On the P&S AND the dSLR, you first must know how big the sensor is. This is because the sensor size determines how a specific focal length acts. With a tiny 1/1.25" sensor a 70mm lens is a giant telephoto. On a dSLR with a "APS-C" size sensor, that 70mm lens is a medium telephoto. On a FF (35mm) dSLR, the 70mm lens is a long standard lens. The size of the sensor determines the angle-of-view that the sensor/lens combo "sees".

Go here. Download the program and select a camera and a lens and look at the field-of-view to see the effect:

http://www.stegmann.dk/mikkel/barnack/

--
Charlie Davis
Nikon 5700, Sony R1, Nikon D300
HomePage: http://www.1derful.info
Bridge Blog: http://www.here-ugo.com/BridgeBlog/
'Experience: Discovering that a claw hammer will bend nails.
Epiphany: Discovering that a claw hammer is two tools...'

 

[Bruce Edwards]

--
Thanks Charlie.

Makes sense.

Here's a little more detail. The point and shoot is a 1st gen Sony ultra zoom with a 10x quoted zoom. (Sony H1) CCD sensor (1/2.4")
http://www.dpreview.com/reviews/specs/Sony/sony_dsch1.asp

The 70-300mm is mounted on a Nikon D90, with a CMOS sensor (23.6 x 15.8 mm).

At 10x zoom on the Sony, would I be tighter in on an object as compared to zoomed in at 300mm on the Nikon?

Sorry to have repeated a question, but I am sure you know search is horrible here (something I see they plan on fixing soon).

Thanks again, in advance.

 

[BA baracus]

Still not enough info for what you are asking.

Looking at DPreview's H1 spec sheet it looks like at tele end the field of view is same as 432mm for 35mm. A 300mm on a D90 would be 450mm (300mm x 1.5 crop=450mm field of view). So a 70-300 can fill the frame more than the H1.

 

[chuxter]

--
Thanks Charlie.

You are welcome, but you'd be MORE welcome if you did more of the "leg work" yourself. Didn't I give you a link to Barnack? It's the tool you need to answer your current question and likely future ones too.

Makes sense.

Here's a little more detail. The point and shoot is a 1st gen Sony
ultra zoom with a 10x quoted zoom. (Sony H1) CCD sensor (1/2.4")
http://www.dpreview.com/reviews/specs/Sony/sony_dsch1.asp

That list of specs tells you the answer to your question...sorta. It says that the H1 has a max effective (ie, in 35mm film terms) of 432mm. It also says it has a 12X zoom range!

I'll trade you a dpr link:

http://www.dpreview.com/reviews/sonydsch1/

Look at the pic at the top. It also shows the 12X label on the side of the camera. Look at the front of the lens...see the writing...read "f = 6.0 - 72mm". That is the REAL FL of the lens. Goto Barnack and plug in the numbers and you'll see that both cameras with the stated lenses have essentially the same horiz. FOF: 3 degrees. But with only one digit of precision, I'd suspect that the H1 @ 432mm gives a slightly bigger FOV than the D90 w/ 300mm (because the D90 is a 1.5-crop camera, so the 300mm lens is effectively a 450mm lens. 450mm is a bit "longer" than 432mm).

The 70-300mm is mounted on a Nikon D90, with a CMOS sensor (23.6 x
15.8 mm).

At 10x zoom on the Sony, would I be tighter in on an object as
compared to zoomed in at 300mm on the Nikon?

Sorry to have repeated a question, but I am sure you know search is
horrible here (something I see they plan on fixing soon).

Some things can't be effectively searched for. Your question is one of them. But it's easy to get the answer with the tool I pointed you to.

Thanks again, in advance.

--
Charlie Davis
Nikon 5700, Sony R1, Nikon D300
HomePage: http://www.1derful.info
Bridge Blog: http://www.here-ugo.com/BridgeBlog/
'Experience: Discovering that a claw hammer will bend nails.
Epiphany: Discovering that a claw hammer is two tools...'

 

[Smithhill]

-- Yes, always confusing when we talk about a 400 mm lens. Is that actual measurement, a 35 equivalent, or an equivalent when related to the type of camera it was designed for? So, understand the best we can and muddle through.

To add real confusion to the conversation consider digiscoping magnification. I have an 8 meg Canon A-590 coupled with a 23 inch lens and a 20mm eyepiece. Wanting real figures I measured the magnification with and without the digiscope attachment, assigned a 35 mm equivalent focal length of 40mm to the camera, and calculated a 35mm equivalent of 1200mm for the system.

This would be 30X. 40X with a small recommended amount of camera zoom. Check out a typical image at: http://www.NaturePicks1.Gallery1.photoshare.co.nz Click on the bluebird thumb and then on the Original size to bring up detail. I say not bad for a total cost of about $200 for the camera, lens, and Expanse eyepiece, at 30 feet. Not counting my fabrication labor costs at 10 cents per hour.

 

[MaryGierth]

Can someone settle this for me? I don't understand what the
correlation between say 10x zoom on a Point and Shoot is when
referring to say a Nikon 70-300mm lens.

Which one has the longest reach? And what would the 300mm on the
Nikon be equivalent to if using the "numberx" value?

Thanks!

It seems to me you are asking two (or more questions here). But I don't think anyone has responded to your "which has the longest reach" question. The responses seem to address the issues of zoom ratio calc and effective focal length/field of view but not focal length/magnification. Isn't magnification or reach just a matter of comparing the actual focal length of the various lenses? Chuxter, anyone?

 

[BA baracus]

It seems to me you are asking two (or more questions here). But I
don't think anyone has responded to your "which has the longest
reach" question. The responses seem to address the issues of zoom
ratio calc and effective focal length/field of view but not focal
length/magnification. Isn't magnification or reach just a matter of
comparing the actual focal length of the various lenses? Chuxter,
anyone?

I stated it yesterday and Chuxter did the same today.

H1 has a 72mm lens at longest FL.
D90 with 70-300 has 300mm at longest FL

Change those to 35mm field of view equivalents and the H1 is 432mm and D90 is 450mm.

So the D90+70-300 would have the longest reach in this case, 18mm at that range is not going to be very noticeable.
--

 

[MaryGierth]

It seems to me you are asking two (or more questions here). But I
don't think anyone has responded to your "which has the longest
reach" question. The responses seem to address the issues of zoom
ratio calc and effective focal length/field of view but not focal
length/magnification. Isn't magnification or reach just a matter of
comparing the actual focal length of the various lenses? Chuxter,
anyone?

I stated it yesterday and Chuxter did the same today.

H1 has a 72mm lens at longest FL.
D90 with 70-300 has 300mm at longest FL

Change those to 35mm field of view equivalents and the H1 is 432mm
and D90 is 450mm.

So the D90+70-300 would have the longest reach in this case, 18mm at
that range is not going to be very noticeable.
--

Those are field of view equivalents, not magnification equivalents.

 

[tkbslc]

I think some people are giving you difficult answers. There is an easier way to look at this. First off, ignore the 10x/12x. etc specs. They are just comparing the lens to itself. Meaning it zooms in 10x farther than it starts. That doesn't help compare to other cameras. What if one camera starts at 28mm and the other 40mm? 10x them both and the one that starts at 40 is longer.

So, look at the specs for the camera that has 10x zoom. It will probably say 35mm equiv length of xx-xxx. For most 10x zoom that is around 35-350mm give or take. Now take the 70-300mm lens. If you put that on a D90, that has a 1.5x crop. So you times the numbers by 1.5 and you get 105-450mm 35mm equivalent. On a 35mm film or "full frame" camera you just use the length of the lens, so 70-300 equals 70-300mm. Now that you have everything converted to 35mm equivalents, you can compare. in this example, the 450mm equivalent of the 70-300 on the nikon d90 is the "most zoomed" and will get you a more magnified image.

If you are considering this lens to be a sole replacement for a 10x zoom compact camera, you will be missing a lot of close range. the 105mm equivalent starting zoom is already too long to take pictures of anything close. You'd want a standard zoom like a 18-55 or 18-70 to go with the lens to take pictures of anything not small or far away.

 

[chuxter]

Mary, field-of-view is the best way to express "reach". To try to explain what "magnification" means would involve getting pedantic and writing a book. Even after that, mag is rather worthless, IMO.

I DID explain that the OP's 10X camera did not have 10X magnification...as did others.

Those are field of view equivalents, not magnification equivalents.

--
Charlie Davis
Nikon 5700, Sony R1, Nikon D300
HomePage: http://www.1derful.info
Bridge Blog: http://www.here-ugo.com/BridgeBlog/
'Experience: Discovering that a claw hammer will bend nails.
Epiphany: Discovering that a claw hammer is two tools...'

 

[chuxter]

I think some people are giving you difficult answers.

Yes, but BA and I didn't. ;-)

--
Charlie Davis
Nikon 5700, Sony R1, Nikon D300
HomePage: http://www.1derful.info
Bridge Blog: http://www.here-ugo.com/BridgeBlog/
'Experience: Discovering that a claw hammer will bend nails.
Epiphany: Discovering that a claw hammer is two tools...'

 

[MaryGierth]

Mary, field-of-view is the best way to express "reach". To try to
explain what "magnification" means would involve getting pedantic and
writing a book. Even after that, mag is rather worthless, IMO.

I DID explain that the OP's 10X camera did not have 10X
magnification...as did others.

This link helped me understand the difference between field of view and magnification. Not sure why mag is worthless. Consider how expensive the long telephotos are, there is no way they are the same as the effective focal length on a crop camera. I've seen people comment that buying an Olympus is better than a Nikon because you get more telephoto with the lenses.

http://www.dpreview.com/learn/?/Glossary/Optical/Focal_Length_Multiplier_01.htm

 

[chuxter]

Mary, field-of-view is the best way to express "reach". To try to
explain what "magnification" means would involve getting pedantic and
writing a book. Even after that, mag is rather worthless, IMO.

I DID explain that the OP's 10X camera did not have 10X
magnification...as did others.

This link helped me understand the difference between field of view
and magnification. Not sure why mag is worthless.

1) It's worthless because magnification is a RATIO...ie, it's 10X bigger than something...and that something is seldom stated. Related to photography, if we used magnification instead of focal length, what would be the unstated reference? I suppose we could define the "1X" FL to be 43mm for a FF 35mm format and extract 30 degree horizontal FOV from that. In this way, any lens that gives a 30 degree horiz. FOV would be called a "1X" lens...regardless of the actual FL. Isn't it obvious that calling it a 30 degree FOV lens is just as good, if not better?

2) It's worthless because many people will be confused by "3X Zoom" and a binocular with a stated 10-power.

Consider how
expensive the long telephotos are, there is no way they are the same
as the effective focal length on a crop camera. I've seen people
comment that buying an Olympus is better than a Nikon because you get
more telephoto with the lenses.

I'm confused by your above sentences? How does this relate to "magnification"?

--
Charlie Davis
Nikon 5700, Sony R1, Nikon D300
HomePage: http://www.1derful.info
Bridge Blog: http://www.here-ugo.com/BridgeBlog/
'Experience: Discovering that a claw hammer will bend nails.
Epiphany: Discovering that a claw hammer is two tools...'

 

[MaryGierth]

Mary, field-of-view is the best way to express "reach". To try to
explain what "magnification" means would involve getting pedantic and
writing a book. Even after that, mag is rather worthless, IMO.

I DID explain that the OP's 10X camera did not have 10X
magnification...as did others.

This link helped me understand the difference between field of view
and magnification. Not sure why mag is worthless.

1) It's worthless because magnification is a RATIO...ie, it's 10X
bigger than something...and that something is seldom stated. Related
to photography, if we used magnification instead of focal length,
what would be the unstated reference? I suppose we could define the
"1X" FL to be 43mm for a FF 35mm format and extract 30 degree
horizontal FOV from that. In this way, any lens that gives a 30
degree horiz. FOV would be called a "1X" lens...regardless of the
actual FL. Isn't it obvious that calling it a 30 degree FOV lens is
just as good, if not better?

2) It's worthless because many people will be confused by "3X Zoom"
and a binocular with a stated 10-power.

Consider how
expensive the long telephotos are, there is no way they are the same
as the effective focal length on a crop camera. I've seen people
comment that buying an Olympus is better than a Nikon because you get
more telephoto with the lenses.

I'm confused by your above sentences? How does this relate to
"magnification"?

My understanding of the effect of the crop factor is derived from this link:

http://www.dpreview.com/learn/?/Glossary/Optical/Focal_Length_Multiplier_01.htm

This is the way I interpret the info on this link. I'll start with an analogy.

You have two buckets that are each 3/4th filled with water. Which bucket has more water? Depends on the size of the bucket. A gallon bucket 3/4ths full has more water in it than a quart size bucket 3/4ths full.

In relating this to the crop factor issue of field of view and mag here is my analogy. You have two sensors, one the size of a postage stamp and one the size of a baseball card. Each has a lens that will magnify the same subject so that the subject covers 75% of the sensor. Which lens has greater magnification. IMO the lens that projects an image covering more area has greater magnification. This would be the lens that projects on the the baseball card size sensor.