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05/11/2010 10:08:44 AM · #1 |
| I've been giving some thought to upgrading my lenses and have been examining some examples on the site. One thing I noticed no info for is the focal length used. This could be helpful in evaluating the performance of lenses. |
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05/11/2010 10:49:18 AM · #2 |
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05/11/2010 11:50:01 AM · #3 |
| Thirded. Straight from the EXIF data... |
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05/11/2010 12:04:19 PM · #4 |
| Four'thed! That would be a sweet feature! |
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05/11/2010 12:17:27 PM · #5 |
| agreed ... I've often wondered what focal length some of the images were taken at ... |
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05/11/2010 12:50:10 PM · #6 |
| yes, is a good idea for me too... |
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05/11/2010 01:19:28 PM · #7 |
One problem is that depending on crop factor and manufacturer specifications the focal length is often recorded in a sort-of code instead of openly. For example, my camera's FL ranges from 6mm-72mm as recorded by the EXIF (see below), you have to multiply by 6 to get something like the advertised 35mm-equivalent of 36-412mm ...
Originally posted by Canon S3 IS EXIF:
File: - IMG_0365.JPG
Make - Canon
Model - Canon PowerShot S3 IS
ShutterSpeedValue - 1/79 seconds
ApertureValue - F 3.51
ExposureBiasValue - 0.00
MaxApertureValue - F 2.71
MeteringMode - Center weighted average
Flash - Not fired, compulsory flash mode
FocalLength - 6.00 mm
ColorSpace - sRGB
ExifImageWidth - 2816
ExifImageHeight - 2112
ExposureMode - Manual
WhiteBalance - Auto
DigitalZoomRatio - 1.00 x
Exposure mode - Manual
Focal length - 600 - 7200 mm (100 mm)
Subject Distance - 12 |
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05/11/2010 01:34:47 PM · #8 |
Originally posted by GeneralE:
One problem is that depending on crop factor and manufacturer specifications the focal length is often recorded in a sort-of code instead of openly. For example, my camera's FL ranges from 6mm-72mm as recorded by the EXIF (see below), you have to multiply by 6 to get something like the advertised 35mm-equivalent of 36-412mm ... |
Yep, your EXIF is recording the physical (actual) focal length of the lens. Most cameras will probably report this way, and I'm almost certain that all DSLRs will do so. If you know the focal length and the type of camera, you have a good idea about what the number means. For DSLRs this is pretty straight forward; 90% of all DSLRs are either 35mm frame or APS-C, with other permutations, e.g. 4/3, micro 4/3 thrown in for good measure. The minor variations within APS-C (Canon at 1.6x, Nikon at 1.5x) are really pretty insignificant. |
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05/11/2010 02:10:45 PM · #9 |
So forget the EXIF. Just have a field we can fill in for focal length, and one for 35mm equivalent focal length. Sounds easy enough to me.
Oh, and don't make them "required fields" for Critique Club eligibility. |
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05/11/2010 02:20:17 PM · #10 |
Originally posted by George:
So forget the EXIF. Just have a field we can fill in for focal length, and one for 35mm equivalent focal length. Sounds easy enough to me.
Oh, and don't make them "required fields" for Critique Club eligibility. |
No, no... I think pulling it from the EXIF is fine... Anyone who actually cares about this information will be fully capable of doing the required math, and should be knowledgeable enough to know that the conversion is needed.
I've thought about asking for this before... Please do this. Please? :) please. :) :) |
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05/12/2010 09:42:17 PM · #11 |
I'd love to see a fieled for this as well. Just one needed... add the equivalent for your lens.
Ex:
30mm (45 equiv) |
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05/12/2010 09:45:20 PM · #12 |
Originally posted by coryboehne:
Originally posted by George:
So forget the EXIF. Just have a field we can fill in for focal length, and one for 35mm equivalent focal length. Sounds easy enough to me.
Oh, and don't make them "required fields" for Critique Club eligibility. |
No, no... I think pulling it from the EXIF is fine... Anyone who actually cares about this information will be fully capable of doing the required math, and should be knowledgeable enough to know that the conversion is needed.
I've thought about asking for this before... Please do this. Please? :) please. :) :) |
Personally, I always use "save for web" for my dpc pictures. Therefore, there is no exif data available. |
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05/12/2010 09:50:17 PM · #13 |
Originally posted by George:
So forget the EXIF. Just have a field we can fill in for focal length, and one for 35mm equivalent focal length. Sounds easy enough to me. |
When you submit an entry (or Portfolio image) there's a text field where you can type in additional information about how you acquired and processed the photo. There's already a place to enter which lens you used -- is it that much work to type
FL = 67mm
in that area? |
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05/12/2010 09:52:15 PM · #14 |
Originally posted by GeneralE:
Originally posted by George:
So forget the EXIF. Just have a field we can fill in for focal length, and one for 35mm equivalent focal length. Sounds easy enough to me. |
When you submit an entry (or Portfolio image) there's a text field where you can type in additional information about how you acquired and processed the photo. There's already a place to enter which lens you used -- is it that much work to type
FL = 67mm
in that area? |
That's sensible, but it's not leading towards any sortable or searchable database capabilities. Still, you're right; it's easy enough to enter that data in the open field.
R.
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05/12/2010 09:56:59 PM · #15 |
Originally posted by GeneralE:
FL = 67mm
in that area? |
Well, the lens field is a drop down list box, but good idea to use the notes field. Creating a field for it encourages people to enter the info, however. Isn't really a biggie, I didn't mean to stir a debate. |
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05/12/2010 10:06:04 PM · #16 |
Providing a text field to fill in manually near the other exposure area would be fine, especially if there was some explanation near it. The problem is in parsing the EXIF because the inconsistency in how the information is recorded would make the number rather useless, and programming the conversion from every camera/lens combination should not really be the site's responsibility (IMO). Something like this (that's a small text box) just below the lens drop-down field might work:
Focal Length [_____]mm (35mm equivalent)
Message edited by author 2010-05-12 22:06:26. |
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05/12/2010 10:19:02 PM · #17 |
Originally posted by GeneralE:
Providing a text field to fill in manually near the other exposure area would be fine, especially if there was some explanation near it. The problem is in parsing the EXIF because the inconsistency in how the information is recorded would make the number rather useless, and programming the conversion from every camera/lens combination should not really be the site's responsibility (IMO). Something like this (that's a small text box) just below the lens drop-down field might work:
Focal Length [_____]mm (35mm equivalent) |
That would be lovely...
R.
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05/12/2010 11:13:26 PM · #18 |
Originally posted by GeneralE:
Originally posted by George:
So forget the EXIF. Just have a field we can fill in for focal length, and one for 35mm equivalent focal length. Sounds easy enough to me. |
When you submit an entry (or Portfolio image) there's a text field where you can type in additional information about how you acquired and processed the photo. There's already a place to enter which lens you used -- is it that much work to type
FL = 67mm
in that area? |
It honestly has little or nothing to do with the difficulty of typing it in..
It's just that most people simply do not bother, and that's a bit of a shame, since it would be super cool info to have. Once again, this is a pixel-peeper's dream, obviously not useful to most, but it would be superb to have available. And in any case, I would actually prefer the recorded length vs. the equivalent length...
Cheers.. |
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05/12/2010 11:15:30 PM · #19 |
Originally posted by GeneralE:
Providing a text field to fill in manually near the other exposure area would be fine, especially if there was some explanation near it. The problem is in parsing the EXIF because the inconsistency in how the information is recorded would make the number rather useless, and programming the conversion from every camera/lens combination should not really be the site's responsibility (IMO). Something like this (that's a small text box) just below the lens drop-down field might work:
Focal Length [_____]mm (35mm equivalent) |
Again.. Please understand that the techies out there who want this information, do not need the equivalent length... The "as recorded" length would be perfectly fine, as we should know how to convert the actual length to a 35mm equivalent...
(If you're counting on people filling this in to do their own conversion math, there are likely to be big errors, as math is not everyone's strong suit... Again, probably better to simply use "as recorded EXIF length"....)
Message edited by author 2010-05-12 23:18:11. |
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05/12/2010 11:25:50 PM · #20 |
Originally posted by coryboehne:
Originally posted by GeneralE:
Providing a text field to fill in manually near the other exposure area would be fine, especially if there was some explanation near it. The problem is in parsing the EXIF because the inconsistency in how the information is recorded would make the number rather useless, and programming the conversion from every camera/lens combination should not really be the site's responsibility (IMO). Something like this (that's a small text box) just below the lens drop-down field might work:
Focal Length [_____]mm (35mm equivalent) |
Again.. Please understand that the techies out there who want this information, do not need the equivalent length... The "as recorded" length would be perfectly fine, as we should know how to convert the actual length to a 35mm equivalent...
(If you're counting on people filling this in to do their own conversion math, there are likely to be big errors, as math is not everyone's strong suit... Again, probably better to simply use "as recorded EXIF length"....) |
It's simple for most DSLR's, assuming you know the "crop factor" for the various cameras, but what about the myriad of non-dslr cameras? |
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05/12/2010 11:28:04 PM · #21 |
Originally posted by Spork99:
Originally posted by coryboehne:
Originally posted by GeneralE:
Providing a text field to fill in manually near the other exposure area would be fine, especially if there was some explanation near it. The problem is in parsing the EXIF because the inconsistency in how the information is recorded would make the number rather useless, and programming the conversion from every camera/lens combination should not really be the site's responsibility (IMO). Something like this (that's a small text box) just below the lens drop-down field might work:
Focal Length [_____]mm (35mm equivalent) |
Again.. Please understand that the techies out there who want this information, do not need the equivalent length... The "as recorded" length would be perfectly fine, as we should know how to convert the actual length to a 35mm equivalent...
(If you're counting on people filling this in to do their own conversion math, there are likely to be big errors, as math is not everyone's strong suit... Again, probably better to simply use "as recorded EXIF length"....) |
It's simple for most DSLR's, assuming you know the "crop factor" for the various cameras, but what about the myriad of non-dslr cameras? |
Many of the P&S cams are about a 6x crop.. |
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05/13/2010 12:55:20 AM · #22 |
Originally posted by coryboehne:
Originally posted by Spork99:
Originally posted by coryboehne:
Originally posted by GeneralE:
Providing a text field to fill in manually near the other exposure area would be fine, especially if there was some explanation near it. The problem is in parsing the EXIF because the inconsistency in how the information is recorded would make the number rather useless, and programming the conversion from every camera/lens combination should not really be the site's responsibility (IMO). Something like this (that's a small text box) just below the lens drop-down field might work:
Focal Length [_____]mm (35mm equivalent) |
Again.. Please understand that the techies out there who want this information, do not need the equivalent length... The "as recorded" length would be perfectly fine, as we should know how to convert the actual length to a 35mm equivalent...
(If you're counting on people filling this in to do their own conversion math, there are likely to be big errors, as math is not everyone's strong suit... Again, probably better to simply use "as recorded EXIF length"....) |
It's simple for most DSLR's, assuming you know the "crop factor" for the various cameras, but what about the myriad of non-dslr cameras? |
Many of the P&S cams are about a 6x crop.. |
But again, many aren't, especially the "prosumer" cams like the G11 and the S90, both of which have "larger sensors than the standard P&S cameras. And "about" isn't very precise.
I'm not saying your suggestion is a bad idea, I'm just saying that it may not be as simple as it seems. |
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05/13/2010 04:22:33 AM · #23 |
Originally posted by Spork99:
Originally posted by coryboehne:
Originally posted by Spork99:
It's simple for most DSLR's, assuming you know the "crop factor" for the various cameras, but what about the myriad of non-dslr cameras? |
Many of the P&S cams are about a 6x crop.. |
But again, many aren't, especially the "prosumer" cams like the G11 and the S90, both of which have "larger sensors than the standard P&S cameras. And "about" isn't very precise.
I'm not saying your suggestion is a bad idea, I'm just saying that it may not be as simple as it seems. |
In the end, it's either take it as-is from EXIF, or use a manual entry system. Frankly, I think that pulling it from the EXIF has far more merit, no matter what the difficulties..
Message edited by author 2010-05-13 04:23:49. |
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