snubbr.com

Aspect Ratio and Angle of View
Hi,.

Some cameras like the Panasonic LX2 have a sensor that has a true 16:9 aspect ratio. This particular camera comes also equiped with a 28mm lens (35mm equivalent of course)..

This is where, for me, things get a bit confusing..

The aspect ratio of the "35mm equivalent" part of a 28mm lens is not 16:9 but 3:2. I am assuming here that the angle of view of that lens is the same independant of the aspect ratio of the sensor that is to say about 75 degrees diagonal. Is this correct?.

So a photo of the same scene taken with 2 *different* cameras, one with a 16:9 sensor, the other with a 4:3 sensor, but both having a 28mm lens will capture all elements of that scene? Nothing will be missing? Only the aspect ratio will change. Seems a bit conter-intuitive but that's the way it is, right?.

If this is correct would the 16:9 photo then convey the impression, psychological for lack of a better word, that it is actually wider then the identical 4:3 photo even though both have an angle of view of 75 degree. It would seem to me that this is the case simply because the 16:9 aspect ratio IS wider then 4:3 or 3:2..

Anybody have example of the same scene taken with 2 different cameras? It has to be different cameras, because even though you can change the aspect ratio on the LX2 and other cameras, doing so changes the angle of view..

Thanks....

Jml9905..

Comments (10)

You'll just go nuts trying to figue this stuff out..

The camera makers, the lens makers, the magazines, the marketing departments all have different approaches, so it is almost impossible to determine..

Your 16:9, or course, is not a common still phto ratio. It's television..

Ratios have been confusing for years; what good does it do you to know the 3:2 ratio of a typical digital single lens reflextx camera, when the 8x10 print is a 4:5 ratio?.

Sometimes the excuse various equivilent-mathematicians use is to look at the diagonal, from, say, lower left to upper right. This even lets people compare a square format (think Hasselblad) with a 35mm frame..

BEST ADVICE; forgt about the 16:9 stuff, and just worry about 4:3 and 2:3, and then be flexible..

BAK..

Comment #1

An easy way to look at this would be to take the picture with a 4:3 camera.The angle of view is set to aquire 75 degrees per your example.Now just crop the picture to 3:2 and 16:9.....what have you done?.

The horizontal angle of view is unchanged, but the vertical angle of view has narrowed..

So far so good. But angle of view can also be described in the vertical dimension and even the diagonal dimension. If you do so you will find that it takes different horizontal angles of view to accomplish the same vertical or diagonal angles of view and thus different lenses and different things will be in the picture..

I find it easiest to stick to the horizontal AOV when comparing lenses. YMMV.A member of the rabble in good standing...

Comment #2

So a photo of the same scene taken with 2 *different* cameras, onewith a 16:9 sensor, the other with a 4:3 sensor, but both having a28mm lens will capture all elements of that scene? Nothing will bemissing? Only the aspect ratio will change. Seems a bitconter-intuitive but that's the way it is, right?.

If this is correct would the 16:9 photo then convey the impression,psychological for lack of a better word, that it is actually widerthen the identical 4:3 photo even though both have an angle of viewof 75 degree. It would seem to me that this is the case simplybecause the 16:9 aspect ratio IS wider then 4:3 or 3:2..

No, they will capture different amounts of the scene. Imagine comparing three sensors: one is 1 x 1.5 cm (the usual 2:3 ratio of most DSLRs), one is 1 x 1.33 cm (the 4:3 ratio of Olympus cameras) and one is 1 x 1.77 cm (the widescreen 16:9 ratio). They will capture the same amount of the scene vertically (the 1cm dimension), but the field of view captured by the sensor will extend sideways to different extents; the 1 x 1.77 sensor will capture a lot more at the sides of the picture than the 1 x 1.33 sensor which is more tightly cropped..

If this were not so, and the different ratio sensors captured the same amount of the scene, that could only happen if the image were distorted (stretched or compressed) horizontally..

Just imagine taking a large poster picture (analogy for the whole field of view provided by a given lens)... and then cutting out of the middle 1 x 1.33, 1 x 1.5 or 1 x 1.77 rectangles..

Best wishesMike..

Comment #3

Jml9905 wrote:.

The aspect ratio of the "35mm equivalent" part of a 28mm lens is not16:9 but 3:2. I am assuming here that the angle of view of that lensis the same independant of the aspect ratio of the sensor that is tosay about 75 degrees diagonal. Is this correct?.

So a photo of the same scene taken with 2 *different* cameras, onewith a 16:9 sensor, the other with a 4:3 sensor, but both having a28mm lens will capture all elements of that scene? Nothing will bemissing? Only the aspect ratio will change..

If this is correct would the 16:9 photo then convey the impression,psychological for lack of a better word, that it is actually widerthen the identical 4:3 photo even though both have an angle of viewof 75 degree..

The confusion comes from being wrong..

The cameras produce images that have the same aspect ratio as their sensor. Two sensors of different aspects will NOT capture "all elements of that scene" identically. How could they? A photo of a sphere in either camera had better turn out to be a perfect circle (not an oval) in the photograph, or it would be useless..

Television is going through this horrible mess right now. At first it was the widescreen/fullscreen product choices. Show a cinematic movie on a TV and you must either crop out a third of the movie and constantly change the included area to keep actors in view ("pan and scan"), or you must reduce resolution and add dead black areas to the top and bottom. Now HDTV and 16:9 tubes are compounding the problem: go to a showroom and you will see many mis-configured sets which make everybody look fat or skinny because they rescan to the wrong aspect ratio..

The fields of view are not always measuring the diagonal, but whether they do or not, they must be changed to reflect the actual image area captured. You *could* refer to the image circle inside the camera, which would not change with sensor shape and size, but that would tend to confuse things more for that very reason..

[ e d @ h a l l e yc c ] http://www.halley.cc/pix/..

Comment #4

That's why I would like to see the result from 2 different cameras, one with a 16:9 sensor and the other with a 4:3 or 3:2. Lots of P&S can take picture in different aspect ratio but they do this by cropping the picture and as you say when that happens you are changing the angle of view either vertically or horizontally..

I'm just curious to know if the vertical angle of view of the LX2 lens at 28mm is different from a 28mm lens on a 4:3 aspect ratio sensor. Does it optically or physically need to be different? Or can one have the same picture, same diagonal, horizontal and vertical angle of view but projected at 16:9 rather then 4:3? Like BAK said you can go nut trying to figure this out..

I don't print much. Most of my pictures I look at on my 16:10 monitor or my 16:9 tv..

Jml9905.

LM1 wrote:.

An easy way to look at this would be to take the picture with a 4:3camera.The angle of view is set to aquire 75 degrees per your example.Now just crop the picture to 3:2 and 16:9.....what have you done?the horizontal angle of view is unchanged, but the vertical angle ofview has narrowed..

So far so good. But angle of view can also be described in thevertical dimension and even the diagonal dimension. If you do so youwill find that it takes different horizontal angles of view toaccomplish the same vertical or diagonal angles of view and thusdifferent lenses and different things will be in the picture..

I find it easiest to stick to the horizontal AOV when comparinglenses. YMMV.A member of the rabble in good standing...

Comment #5

Thanks Ed and Mike.

Both you explanations are clear and I think i'm starting to understand now..

Jml9905.

Ed Halley wrote:.

Jml9905 wrote:.

The aspect ratio of the "35mm equivalent" part of a 28mm lens is not16:9 but 3:2. I am assuming here that the angle of view of that lensis the same independant of the aspect ratio of the sensor that is tosay about 75 degrees diagonal. Is this correct?.

So a photo of the same scene taken with 2 *different* cameras, onewith a 16:9 sensor, the other with a 4:3 sensor, but both having a28mm lens will capture all elements of that scene? Nothing will bemissing? Only the aspect ratio will change..

If this is correct would the 16:9 photo then convey the impression,psychological for lack of a better word, that it is actually widerthen the identical 4:3 photo even though both have an angle of viewof 75 degree..

The confusion comes from being wrong..

The cameras produce images that have the same aspect ratio as theirsensor. Two sensors of different aspects will NOT capture "allelements of that scene" identically. How could they? A photo of asphere in either camera had better turn out to be a perfect circle(not an oval) in the photograph, or it would be useless..

Television is going through this horrible mess right now. At firstit was the widescreen/fullscreen product choices. Show a cinematicmovie on a TV and you must either crop out a third of the movie andconstantly change the included area to keep actors in view ("pan andscan"), or you must reduce resolution and add dead black areas to thetop and bottom. Now HDTV and 16:9 tubes are compounding the problem:go to a showroom and you will see many mis-configured sets which makeeverybody look fat or skinny because they rescan to the wrong aspectratio..

The fields of view are not always measuring the diagonal, but whetherthey do or not, they must be changed to reflect the actual image areacaptured. You *could* refer to the image circle inside the camera,which would not change with sensor shape and size, but that wouldtend to confuse things more for that very reason..

[ e d @ h a l l e yc c ] http://www.halley.cc/pix/..

Comment #6

A point which doesn't seem to have been made very clearly so far is that the diagonal is normally used when specifying the angle of view of a lens. Every manufacturer I know of does this. The diagonal matches the image circle of the lens, and the aspect ratio of the sensor has no effect on this..

When a lens is said to be equivalent to 28 mm, that means that it has the same diagonal field of view as a 28 mm lens on a 35mm camera. Obviously that means that the horizontal and vertical fields of view differ with different aspects ratios, but since neither is inherently more important than the other it doesn't matter..

Picture a circle of a given size, with different shaped rectangles fitting snugly within it, corners just touching the circle. That's how the different aspect ratios work..

I notice one poster claims that he uses horizontal field of view when comparing lenses. Well, that's fine if he prefers it, but (a) not one manufacturer does, and (b) I have yet to meet a photographer who actually uses or even knows the numerical values of the fields of view of any of his lenses!..

Comment #7

Steve Balcombe wrote:.

I have yet to meet a photographer whoactually uses or even knows the numerical values of the fields ofview of any of his lenses!.

Panoramic photographers who stitch images together using some of the more advanced software can calculate and record these values (horizontal AND vertical fields of view) and many others, for each lens at each focal length they're using..

[ e d @ h a l l e yc c ] http://www.halley.cc/pix/..

Comment #8

This has been looked at on the Panny forum in a lot of detail especially when the TZ3 was launched. The TZ3 is unique in that the entire sensor is not used (instead you are utilizing the full image circle from the lens). So, in 16:9, 4:3 and 3:2 all have the same 28mm and none are crops like other cameras. As, somone above mentioned this is measured on the diagonal. However, if your normal "reference" is 4:3 you could ask yourself. What focal length would I need in 4:3 to get the same horizonatal coverage of the 16:9 shot.

But, on the TZ3 the 16:9 picture is not as tall vertically as the 4:3..

On the LX2 the 16:9 sensor gives you the same wider view than you were expecting but when that camera is set to 4:3 unlike the TZ3 there is no extra space on the sensor vertically and your focal length is more like a 31mm.terryhttp://tbanet.zenfolio.com/..

Comment #9

Ed Halley wrote:.

Steve Balcombe wrote:.

I have yet to meet a photographer whoactually uses or even knows the numerical values of the fields ofview of any of his lenses!.

Panoramic photographers who stitch images together using some of themore advanced software can calculate and record these values(horizontal AND vertical fields of view) and many others, for eachlens at each focal length they're using..

Yep, that's fair comment. I'm not sure that it relates much to the OP's situation but it is certainly true...

Comment #10

Click Here to View All...

Sponsored Amazon Deals:

1. Get big savings on Amazon warehouse deals.
2. Save up to 70% on Amazon Products.


This question was taken from a support group/message board and re-posted here so others can learn from it.

 

Categories: Home | Diet & Weight Management | Vitamins & Supplements | Herbs & Cleansing |

Sexual Health | Medifast Support | Nutrisystem Support | Medifast Questions |

Web Hosting | Web Hosts | Website Hosting | Hosting |

Web Hosting | GoDaddy | Digital Cameras | Best WebHosts |

Web Hosting FAQ | Web Hosts FAQ | Hosting FAQ | Hosting Group |

Hosting Questions | Camera Tips | Best Cameras To Buy | Best Cameras This Year |

Camera Q-A | Digital Cameras Q-A | Camera Forum | Nov 2010 - Cameras |

Oct 2010 - Cameras | Oct 2010 - DSLRs | Oct 2010 - Camera Tips | Sep 2010 - Cameras |

Sep 2010 - DSLRS | Sep 2010 - Camera Tips | Aug 2010 - Cameras | Aug 2010 - DSLR Tips |

Aug 2010 - Camera Tips | July 2010 - Cameras | July 2010 - Nikon Cameras | July 2010 - Canon Cameras |

July 2010 - Pentax Cameras | Medifast Recipes | Medifast Recipes Tips | Medifast Recipes Strategies |

Medifast Recipes Experiences | Medifast Recipes Group | Medifast Recipes Forum | Medifast Support Strategies |

Medifast Support Experiences |

 

(C) Copyright 2010 All rights reserved.