Reading mode: Light Dark

Embarrassing question...

  • Thread starter Thread starter avanbeek
  • Start date Start date
Go to last post
A

avanbeek

Guest
Hi,

I have a very basic question as I have never owned a DSLR but would like to move in this direction soon.

What is the deal with the lens factor or whatever it's called where using a 100mm lens gets you the results of a 160mm because of the 1.6 "lens factor".

Is this true? Is it the same for all lenses? How do you use a 14mm wide angle when it gets changed to a 22mm?

I tried to search for more on this and couldn't find anything.

Many thanks,

--

Regards,
AVB
http://www.pbase.com/avanbeek
 
This is because the size of the sensor isn't as big as 35mm film. So, you end up capturing less area and as a result it seems like you've zoomed in by a factor of 1.6x.
A Van Beek said:
Hi,

I have a very basic question as I have never owned a DSLR but would
like to move in this direction soon.
What is the deal with the lens factor or whatever it's called where
using a 100mm lens gets you the results of a 160mm because of the
1.6 "lens factor".

Is this true? Is it the same for all lenses? How do you use a 14mm
wide angle when it gets changed to a 22mm?

I tried to search for more on this and couldn't find anything.

Many thanks,

--

Regards,
AVB
http://www.pbase.com/avanbeek
Click to expand...
--
Regards,

Bill

In my camera bag:
Canon EOS D60
Canon 24-85mm, 28mm f/1.8, 50 f/1.4
Sigma 15-30mm, Sigma 50-500mm
On a shelf: Canon A2e, Nikon Coolpix 995

http://www.photosig.com/viewuser.php?id=20514

http://o2bnme.fotki.com/public/miscellaneous/d60_test_shots/
 
It's not a dumb question. It is a basic fact of life with current digital SLR's. They all basically have a magnification factor... or crop. There have been some very good, highly technical explainations which I'm not going to try to repeat. Lets just say that basically, what you see through the viewfinder looks magnified by whatever factor the camera has. So a 100mm lens on a D60 looks like a 160mm through the viewfinder and that same 100mm lens on a 1D looks like 130mm.

Actually, most sports and wildlife photographers seem to love this feature as it give them more apparent reach with their current lens. However, wide-angle junkies suffer. As you point-out, your ultra-WA 14mm becomes 22.4mm. There is no easy way around this optically.

Fortunately, digital images lend themselves quite easily to be "stitched" together in either the horizontal or vertical direction so you can somewhat easily take a series of shots, stitch them together and come-up with wide angle shots that would be impossible with even the widest lenses available.

-- John
A Van Beek said:
Hi,

I have a very basic question as I have never owned a DSLR but would
like to move in this direction soon.
What is the deal with the lens factor or whatever it's called where
using a 100mm lens gets you the results of a 160mm because of the
1.6 "lens factor".

Is this true? Is it the same for all lenses? How do you use a 14mm
wide angle when it gets changed to a 22mm?

I tried to search for more on this and couldn't find anything.

Many thanks,

--

Regards,
AVB
http://www.pbase.com/avanbeek
Click to expand...
 
A Van Beek said:
Hi,

What is the deal with the lens factor or whatever it's called where
using a 100mm lens gets you the results of a 160mm because of the
1.6 "lens factor".

Is this true? Is it the same for all lenses? How do you use a 14mm
wide angle when it gets changed to a 22mm?
Click to expand...
The chip in the D30/D60 is smaller than the film plane in a 35 mm
camera therefore presenting the effect of 1.6 magnification. If the
chip were the same size as the 35 mm frame the lens would deliver
the same size image for both.
Likewise, when using medium format cameras the opposite effect
is encountered. Example: the 645 format uses an 80 to 90 mm lens
to equal the normal 50 mm lens used in 35 mm film cameras.
When comparing chip and film sizes it would be more appropriate
to use angle of view but this would most likely be even more, for
most people, confusing.
This is why you see many posts asking for a full size chip, meaning
one that is the same size as the 35 mm film frame.
George
Member said:
I tried to search for more on this and couldn't find anything.

Many thanks,

--

Regards,
AVB
http://www.pbase.com/avanbeek
Click to expand...
--
George Reeves
 
that has the same size sensor as 35mm, so its 50mm lens acts the same with the digital version as with the film version. The problem there, besides cost, is that there's not much lens selection so you still can't get a real wide angle lens.

I was reading about a digital back for my Contax 645 the other day. Seems the sensor for it is the same size as 35mm film, so my super wide 35mm Zeiss would just barely be a wide angle lens with the digital back.
 
It affects all of them. It is caused by the active element being a bit smaller than 35 mm frame. Thus, edges of regular 35mm film photo are not used.

This has some interesting side effects.

Lens length gets multiplied by 1.6 but image characteristincs stay the same. In other words, if you did portraits with 80mm, continue to do so (although you will have to move further from the object).

As I already said, the edges of regular 35mm film image are not used. Since most of cheap lenses are bad especially on edges, these may produce acceptable pictures in Cannon DSLRs. This may save you big $$$ if you want the wide angle. Read more at: http://www.luminous-landscape.com/reviews/lenses/sigma_14mm.shtml

Regards,
Pawel
A Van Beek said:
Hi,

I have a very basic question as I have never owned a DSLR but would
like to move in this direction soon.
What is the deal with the lens factor or whatever it's called where
using a 100mm lens gets you the results of a 160mm because of the
1.6 "lens factor".

Is this true? Is it the same for all lenses? How do you use a 14mm
wide angle when it gets changed to a 22mm?

I tried to search for more on this and couldn't find anything.

Many thanks,

--

Regards,
AVB
http://www.pbase.com/avanbeek
Click to expand...
 
Thanks all,

I figured this was the case and I understand the optical physics side pretty well. I just can't believe that this is the case and that people accept this at all. Who wants to but a super expensive 14mm just to get 22.4? I love really wide angles and I don't think I could accept this limitation. Oh well, things will change eventually

AVB
A Van Beek said:
Hi,

I have a very basic question as I have never owned a DSLR but would
like to move in this direction soon.
What is the deal with the lens factor or whatever it's called where
using a 100mm lens gets you the results of a 160mm because of the
1.6 "lens factor".

Is this true? Is it the same for all lenses? How do you use a 14mm
wide angle when it gets changed to a 22mm?

I tried to search for more on this and couldn't find anything.

Many thanks,

--

Regards,
AVB
http://www.pbase.com/avanbeek
Click to expand...
--

Regards,
AVB
http://www.pbase.com/avanbeek
 
A Van Beek said:
Thanks all,

I figured this was the case and I understand the optical physics
side pretty well. I just can't believe that this is the case and
that people accept this at all. Who wants to but a super expensive
14mm just to get 22.4? I love really wide angles and I don't think
I could accept this limitation. Oh well, things will change
eventually
Click to expand...
Well, it goes both ways. I like having the 1.6 multiplier for the long side and I care less about the WA. Actually my 28-135 with the multiplier is wide enough for me, and I prefer to shoot panos most of the time.

So, well, depends on your shooting style.

--
Canon D30
My photo gallery: http://www.pbase.com/davidp
 
If you were to buy a Canon 1D, you'd get a 1.3x factor instead of a 1.6x factor. This would make the 14mm lens approximately a 18.2mm FOV on the 1D.

Plus you get a weather resistant body, fast AF, incredilby large buffer, etc...

Only the Contax N Digital uses a larger sensor than the Canon 1D.

Joo
A Van Beek said:
I figured this was the case and I understand the optical physics
side pretty well. I just can't believe that this is the case and
that people accept this at all. Who wants to but a super expensive
14mm just to get 22.4? I love really wide angles and I don't think
I could accept this limitation. Oh well, things will change
eventually

AVB
A Van Beek said:
Hi,

I have a very basic question as I have never owned a DSLR but would
like to move in this direction soon.
What is the deal with the lens factor or whatever it's called where
using a 100mm lens gets you the results of a 160mm because of the
1.6 "lens factor".

Is this true? Is it the same for all lenses? How do you use a 14mm
wide angle when it gets changed to a 22mm?

I tried to search for more on this and couldn't find anything.

Many thanks,

--

Regards,
AVB
http://www.pbase.com/avanbeek
Click to expand...
--

Regards,
AVB
http://www.pbase.com/avanbeek
Click to expand...
--
  • Canon EOS D-30 & PowerShot S100
  • Maybe one day I'll take a decent picture. In the meantime, I'll blame the equipment. :)
 
The 1.6x magnification factor is a blessing or a curse depending on your requirements at the moment.

Since most of my work is wildlife, it's great. A 300mm f/2.8 lens becomes a 420mm f/2.8 lens without converters. With a 2x it's a 960mm f/5.6 equivalent.

Yes, there are limitations for scenic shots where you want ultra wide angle. But it's not THAT bad. A Tokina 17mm f/3.5 ATX Pro lens is affordable and works out to 28mm. A lot of us remember when a lens lineup in the "old days" consisted of a 28mm wide angle, 50mm "normal lens", 135mm telephoto and maybe a 70-210 zoom.

Good luck!

**** Ginkowski
http://www.pbase.com/dickg/
 
I love the 1.6 multiplier!! There is a group of guys that are just waiting for a full size sensor, while I am hoping it does not happen for a long time.

I love the 1.6 multiplier, all my lenses all of a sudden become much more powerful, AND they become much better because it is using only the best portion of the lens. The edges, where so many lenses are poor are not in the picture so only the best part of the lens is used.

The only time you suffer is when you want very wide lenses. But 14mm, 16mm, and 17mm isn't chopped liver. It really is pretty wide. But 22mm is the widest effective lens on the D60 using 14mm lens and not 14mm. On a 1D, 18mm is the widest effective lens instead of a 14mm.

If Canon releases another high end or middle level camera with a 1.3 mutiplier, the the 18mm will also be it's max width with a 14mm lens.

I would rather have the multiplier than a full frame. I would also like to have a square sensor like my medium format cameras so portrait and landscape shots no longer need the camera to be turned.

Pete
 
I've been doing this sort of thing for a number of years and I like it as well. The problem with this method is the length of time that it takes to set it up and then process it afterwards. It also only works in only one direction at a time (horizontal OR vertical). Work arounds are great when it something new but not as a replacement for functionality that has existed for years.

AVB
John Mason said:
http://www.fototime.com/15C127E3F9C81D7/orig.jpg

18 shots with 24mm L lens shot vertically then stitched on 1.6 crop
factor D30
Click to expand...
--

Regards,
AVB
http://www.pbase.com/avanbeek
 
Peter Gregg said:
I love the 1.6 multiplier, all my lenses all of a sudden become
much more powerful, AND they become much better because it is using
only the best portion of the lens.
Click to expand...
Ya know, something I don't hear mentioned much in association with these digital

sensor "crops" is that, unless I'm mistaken, it "stretches" the resolution of the lens
a bit, relative to a "full-frame" sensor (or regular 35mm film).

Correct me if I'm wrong, but this "1.6x" effect is taken by cropping out the middle of

the image inside the camera. This has a analogous effect (for "old-timers") to cranking

up an enlarger and cropping out the middle of the image, stretching the resolution

of the negative. In other words, if you compare the necessary lens resolution relative

to the size of a final resulting print, a DSLR with a smaller sensor would require higher

resolution to give the same results on the same 8x10 print (assuming lens resolution
is the limiting factor, and not sensor pixel density).

I don't know if lens resolution is really the deciding factor between a good and bad

lens (I'm just a photo hack who has had too much time to ponder empty-handed while

sitting for too long on a D60 waiting list!), but if so, it seems like a sensor that's closer

to full-frame would make your lenses "better" (i.e. it may be cheaper to buy a pricier
body with a larger sensor if it allows you to buy less expensive lenses).

Is this valid logic, or am I confused?
 
(Sorry , that last try was messed up).

Ya know, something I don't hear mentioned much in association with
these digital sensor "crops" is that, unless I'm mistaken, it
"stretches" the resolution of the lens a bit, relative to a
"full-frame" sensor (or regular 35mm frame).

Correct me if I'm wrong, but this "1.6x" effect is taken by
cropping out the middle of the image inside the camera. This
has a analogous effect (for "old-timers") to cranking up an
enlarger and cropping out the middle of the image, stretching
the resolution of the negative. In other words, if you compare
the necessary lens resolution relative to the size of a final
resulting print, a DSLR with a smaller sensor requires higher
resolution to give the same results on the same 8x10 print
(assuming lens resolution is the limiting factor).

I don't know if lens resolution is really the deciding factor
between a good and bad lens (I'm just an amateur who has had
too much time to ponder empty-handed while sitting for too
long on a D60 waiting list!), but if so, it seems like a
sensor that's closer to full-frame would make your lenses
better (i.e. it may be cheaper to buy a pricier body with a
larger senser if it allows you to buy less expensive lenses).
 
First, to simply answer your question, the Field of View (only) is reduced by the 1.6X crop factor. This applies (to a first order) to the use of any focal length.

The "magnification factor" is a marketing concept and has nothing to do with physics. The Lens does not change and there is no "lens factor." The 1.6X factor is a FoV crop. Any "magnfication" is done by a computer by how much it blows up the image. If you want a 3X "multiplier," just crop the image some more.

Now we all get sloppy with language from time to time, but it can get confusing if you are considering anything other than the FoV when you go dow the road of a crop "multiplying" the focal length.

It is true that the crop factor reduces the Field of View by 1.6X on a D30/D60, but there are other optical effects, such as the Depth of Field that are not so simply affected.

Below is a pointer to a post I made a while ago on the effects.

http://www.dpreview.com/forums/read.asp?forum=1019&message=3198915

There could be a reasonable debate/question between whether people would rather have the same number of pixels for a "full" 35mm size frame or would rather have them squeezed into a smaller area. Ignoring the lens resolution effects and the per pixel noise effects (both of which are signification issues in and of themselves), the people that shoot more telephoto would like them squeeze in a smaller area, and those shooting wider angle would rather have them spread over a larger area.

Karl
A Van Beek said:
Hi,

I have a very basic question as I have never owned a DSLR but would
like to move in this direction soon.
What is the deal with the lens factor or whatever it's called where
using a 100mm lens gets you the results of a 160mm because of the
1.6 "lens factor".

Is this true? Is it the same for all lenses? How do you use a 14mm
wide angle when it gets changed to a 22mm?

I tried to search for more on this and couldn't find anything.

Many thanks,

--

Regards,
AVB
http://www.pbase.com/avanbeek
Click to expand...
--
Karl
 
Well, actually what you're saying here is not entirely correct. You are ignoring the fact that due to the change in subject distance you are also changing the depth of field and the perspective.

Depending on the actual subject distance the DOF will increase with a factor of at least the focal length multiplier, and at most it's square. This can of course be adjusted by changing the apperture; open the lense up a bit more. However even if you do that still the perspective will change.

The best way to go would be start using lenses with a shorter focal length and keeping the subject distance the same (i.e. same perspective). However in order to still get the same DOF you will also have to increase the apperture (lower f-stop) with the same factor. In this way you will get almost the same final picture.

Even this approach will fail however if the focal length of the lens is not negliable compared to the subject distance (i.e. macro work). In that case it will be nessecary to open the lens up even more.
Pawel Loj said:
Lens length gets multiplied by 1.6 but image characteristincs stay
the same. In other words, if you did portraits with 80mm, continue
to do so (although you will have to move further from the object).
Regards,
Pawel
Click to expand...
--
In the beginning there was nothing, and then even that exploded.
 
You must log in or register to reply here.

Keyboard shortcuts

f
Forum
m
My threads
Mobile site
About
Editorial content
Cameras & Lenses
Community
All content, design, and layout are Copyright © 1998–2025 Digital Photography Review All Rights Reserved.
Reproduction in whole or part in any form or medium without specific written permission is prohibited.
When you use DPReview links to buy products, the site may earn a commission.
©GPS Media - Guides, Products, Services.
Back
Top