If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#21
|
|||
|
|||
Image size , A technical puzzle.
On 7/10/2015 1:34 AM, Tony Cooper wrote:
On Thu, 9 Jul 2015 20:46:27 -0700, Savageduck wrote: why is there a file size limit at all? especially for small images such as 1024x768. Yup! Again I find myself agreeing. are they running this on an ancient computer with a tiny hard drive such that they don't have enough space for all the entries? a file size limit makes no sense and only motivates people to save in a lower quality with more artifacts. why do they want people to submit ****ty looking photos?? Agreed. It seems to be an odd competition that requires poor quality image files. contests like these are run my morons. the answer is to not participate and optionally try to educate them. I think education would be more productive, unless they are competition tyrants. I think you have to look at it from the viewpoint of the competition committee. My own camera club requires a .jpg with the longest dimension not to be more than 1400 pixels and at 72 ppi for the monthly competitions. We do digital only now. Each competition, will draw in 200 to 300 or more entries between the three catagories (color, b&w, creative) with members allowed two entries (not in the same catagory) each month. The images are sent to the club and the club sends them as a file to each of the three judges who review them and rate them from their home or office on their own computers prior to the meeting night. Whatever the opinion about the 72 ppi limit, all entries are treated equally. The bigger problem is that the judges may or may not have calibrated monitors. An image may be seen differently by different judges, and one may think it's, say, over-saturated and another may not see it that way. The judges are non-paid volunteers, so it's not really possible to demand calibrated monitors. One of the three is an experienced club member, and the other two are always outsiders with some connection or experience in photography. I don't know what Peter is entering, but most of us enter competitions just to have our images critiqued by unbiased outsiders (the submitter is anonymous) and to see our images displayed at the meeting. If everyone's under the same rules, it's a level playing field. There's no money involved, but the last time I won in a catagory I got a $15 gift card from a camera store sponsor. Big whoop. The first time I won I got a year's membership to SmugMug (donated by SmugMug), but that's been a good investment for them because I've continued with my membership, and paid for it, for several years now. BTW...The National Geographic Photo Contest has a file size rule for digital entries : 1600 pixels on the longest side and 20 megabytes or smaller. I guess nospam thinks they are morons, and that's why he's never entered. http://photography.nationalgeographi...contest/rules/ Of course there is no money involved. This is not a commercial comeptition, just at a fun level. In a sense it is similar to our not suspended "Shoot in." I really wish someone would explain why two images with the same pixel dimensions, and saved at the same compression level, would not be the same size. -- PeterN |
#22
|
|||
|
|||
Image size , A technical puzzle.
On 7/10/2015 4:15 AM, nospam wrote:
In article , Tony Cooper wrote: I think you have to look at it from the viewpoint of the competition committee. My own camera club requires a .jpg with the longest dimension not to be more than 1400 pixels and at 72 ppi for the monthly competitions. We do digital only now. What difference would it make if the tag was set to 7 PPI? Or for that matter to 72000 PPI. If it does make some difference, somebody is doing something wrong! It does make a difference. no it doesn't. If I submit an image for a competition that is more than 1400 pixels on the longest side, and/or not 72 ppi, it will be rejected by the computer program that I use to upload the image. It's happened to me. what app is that? regardless, a 72 ppi tag is meaningless. what matters are the pixel dimensions, in your case 1400 or less. I'm not defending the rule. I'm stating what it is. You aren't going to drag me into an argument about why someone else came up with the rule or whether they should have set that rule. Your question, properly asked, is "Why did the competition committee set that rule?". I have no answer for that. I don't set the rules. the answer is because they're clueless dolts who don't understand what they're doing. My guess as to "why?" is that the competition committee wanted to provide some parameters so people wouldn't ask "What ppi should I use?". that's a stupid reason. such a question is an opportunity to teach the person asking what ppi really means and why it makes no difference in an image that won't be printed. True, but some of these images will be printed. unfortunately, a committee who has no clue is not in a position to do that, as they don't understand it themselves. -- PeterN |
#23
|
|||
|
|||
Image size , A technical puzzle.
In article , PeterN
wrote: I recently submitted two images to a competition. Bothe were 100 ppi and measured, in pixels, 1020 x 768, both were saved at the same JPEG compression level. Both files were saved as 8 bit JPEG. there is no ppi in a jpeg file. there is a tag that *suggests* an initial size, such as for a page layout app (and that tag may not necessarily be used, depending on the app), but other than that, the tag is meaningless. ppi only matters when printing. Yes. They intend to print certain images. not very big if the source is 1024x768. that's about 2x3" or so at 300 ppi, possibly 3x4" if they want to accept a little lower quality (250 ppi). anyone who requests a jpeg file at a specific ppi has no clue. See above. the tag doesn't matter. period. the tag might be used to set an *initial* print size (or object size in a layout app), but that's about it. that size can be changed at any time, which will change the ppi, regardless of what the tag specifies. most of the time, the tag is ignored. if they're expecting to get an 8x10 out of it (which is what 100 ppi would do), it's going to look like garbage because 100 ppi is *really* low for printing. ideally it should be 250-300 ppi, depending on intended viewing distance of the print. the pixel dimensions are what matters, and clearly they're stuck in the 1990s if they want it at 1024x768. That may be true, but that is not my issue. One of the images was 500k and the other a tad over 1 mb. it is your issue since you're participating in a competition run by idiots who do not know what they're doing. One of the images was a bit over 500 k. The other was over twice the size. different compression levels and/or different amount of detail. Originally they were both saved at the same level of compression. I had to lower the compression level for the other to conform. Why, is my question. as i said, there are two factors. if compression is the same for both, then the other factor is what will affect the size, that being detail. in other words, one image has more detail than the other, whether it's real detail or sharpening artifacts. |
#24
|
|||
|
|||
Image size , A technical puzzle.
In article , PeterN
wrote: the reason is that they have old projectors which they've probably had for years and refuse to upgrade. it's not like an hdtv projector is that hard to find. Well, evidently you know what equipment all of the Camera Club Councils in the US have. You must have learned that by a survey in Coach. Or, since you've claimed that the people that run the group are highly paid, you took the survey in First Class while peeping through the curtain. How do you come up with this wild hair of a theory, though? Dunno about the NECCC, but the FCCC doesn't project the images at all in the triannual competitions. The images are viewed online by the judges. It says so in their webpage. You wouldn't be making **** up again, would you? If the NEFCCC is run the same as the FCCC (and I suspect it is), Peter will not see his images projected. He will send them in and they will view them online. The NEFCC is in Springfield MA, and Peter is in NY. If he is among the 20/25% who win a ribbon, it will be sent to his local camera club. His image will be up for view in on the NEFCC webpage. Actually, I submitted to a projected image competition, open only to participants in the conference. I will have the opportunity to sit through the judging, if I so desire. in other words, tony is wrong (again) and talking out his ass (again). |
#25
|
|||
|
|||
Image size , A technical puzzle.
In article , PeterN
wrote: I really wish someone would explain why two images with the same pixel dimensions, and saved at the same compression level, would not be the same size. as mentioned in other post, one has more detail than the other. |
#26
|
|||
|
|||
Image size , A technical puzzle.
In article , PeterN
wrote: My guess as to "why?" is that the competition committee wanted to provide some parameters so people wouldn't ask "What ppi should I use?". that's a stupid reason. such a question is an opportunity to teach the person asking what ppi really means and why it makes no difference in an image that won't be printed. True, but some of these images will be printed. it still doesn't matter, and at 1024x768, they won't be printed very large (or they'll look like crap). |
#27
|
|||
|
|||
Image size , A technical puzzle.
On 7/10/2015 4:31 AM, Eric Stevens wrote:
On Fri, 10 Jul 2015 04:15:31 -0400, nospam wrote: In article , Tony Cooper wrote: I think you have to look at it from the viewpoint of the competition committee. My own camera club requires a .jpg with the longest dimension not to be more than 1400 pixels and at 72 ppi for the monthly competitions. We do digital only now. What difference would it make if the tag was set to 7 PPI? Or for that matter to 72000 PPI. If it does make some difference, somebody is doing something wrong! It does make a difference. no it doesn't. If I submit an image for a competition that is more than 1400 pixels on the longest side, and/or not 72 ppi, it will be rejected by the computer program that I use to upload the image. It's happened to me. what app is that? regardless, a 72 ppi tag is meaningless. what matters are the pixel dimensions, in your case 1400 or less. I'm not defending the rule. I'm stating what it is. You aren't going to drag me into an argument about why someone else came up with the rule or whether they should have set that rule. Your question, properly asked, is "Why did the competition committee set that rule?". I have no answer for that. I don't set the rules. the answer is because they're clueless dolts who don't understand what they're doing. The answer is because they have always done it that way. I must digress. I hired an accountant to do some work for a client. He was driving. On the way home we were accompanied by a heavy snow storm. The car heater was turned way up. When I asked him why, he said he liked to drive with the sunroof open in cold weather. When we came to a light, I opened the sunroof. He was not very happy, and didn't get my point. -- PeterN |
#28
|
|||
|
|||
Image size , A technical puzzle.
On 7/10/2015 2:59 AM, Tony Cooper wrote:
On Fri, 10 Jul 2015 02:01:00 -0400, nospam wrote: based on his description, it's neccc, which is a rather well known event with well paid staff. It's an area-wide umbrella organization that any camera club in the New England area can join. Most states, or groups of states, have one. It's not well-known outside of New England any more than the FCCC is well-known outside of Florida. There are CCCs all across the country. I am absolutely amazed that you know the salaries of the people in an organization clear across the country from you. You wouldn't be making **** up again, would you? http://www.neccc.org/p/clubs-join-neccc.html http://www.neccc.org/p/about-us.html limiting entries to 1024x768 and 1 megabyte is stupid. NECCC entries are not limited to 1 megabyte. There's no requirement. The rules say "It is suggested (though not a requirement) that entries be saved with the proper amount of compression so that the file size does not exceed 350 KB. If saving from Photoshop, a quality setting of between 7 and 9 is usually sufficient to produce a high quality file. Keeping the file size below 350 KB makes e-mailing and handling easier." Learn to read before you make a statement. There's no money involved, but the last time I won in a catagory I got a $15 gift card from a camera store sponsor. Big whoop. The first time I won I got a year's membership to SmugMug (donated by SmugMug), but that's been a good investment for them because I've continued with my membership, and paid for it, for several years now. those were the prizes?? Yep. We do it for the glory. Some of us are not afraid to show our photos. The $15 gift card beats what the NECCC and FCCC award: a cheap ribbon. And, chances of winning a ribbon are pretty good. 20 to 25% of the entries win a ribbon according to the websites. It was more difficult to get recognition in the Shoot-In. BTW...there is a cost to enter images at FCCC, but I don't know if that's the case at NECCC. There is no cost to enter my club's competition. My CC does not charge a fee for entries. Our local umbrella organization PFLI, Photographic Federation of Long Island, does not charge a fee either. This NECCC competition is only open to participants in the anual conferance. There is a late fee if the images are not entered by July 12. -- PeterN |
#29
|
|||
|
|||
Image size , A technical puzzle.
On 2015-07-10 12:24:14 +0000, PeterN said:
I really wish someone would explain why two images with the same pixel dimensions, and saved at the same compression level, would not be the same size. Actually two of us have given you an explaination. The file size of two images cropped to identical pixel dimensions is going to be determined by image data content which is a combination of detail area, contrast level and color content. For example, if those two identical dimensioned images were a sky scape with large big color fields with little detail, and shot of a bird with fine plumage detail, the file size for the bird might well be larger. Given that, if you use the LR export method I have explained where the dimensions are set and the file size limited after a crop to a specific aspect ratio you will always be within the set export file size limit. Here are two images cropped and sized to the same aspect ratio one is 11.9 MB the other 16.8 MB On export, where I have set the file size limit at 1000 KB, the first goes from 11.9 MB to 871 KB and the second goes from 16.8 MB to 836 KB. The export dialog forced higher compresion on the larger original, but both are now within the 1000 KB limit for the pixel dimensions I set. They are both 2133 x 1200, or cropped to 16:9. https://db.tt/614ommeD https://db.tt/6buHT51P -- Regards, Savageduck |
#30
|
|||
|
|||
Image size , A technical puzzle.
As others have said, details make the difference. JPG
compresses by dropping out data, which is why over processing shows little rectangles. I just saved a 1020 x 768 JPG at compression level 8 and it's under 5 KB. But it's just a solid blue field, so it's easy to store that data as something that boils down to "783360 instances of pixels of color 0, 0, 256". Interestingly, when I opened the JPG in a hex editor it turns out that most of the 5 KB is just null byte filler. The "start of stream" marker that indicates the beginning of the image data is two bytes, FF DA. The actual image data seems to be only 17 or 18 bytes. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
A brief technical talk about Image Processng Unit (w/ K10D particulars) | RiceHigh | Digital Photography | 0 | January 31st 07 02:46 PM |
A brief technical talk about Image Processng Unit (w/ K10D particulars) | RiceHigh | Digital SLR Cameras | 0 | January 31st 07 02:46 PM |
mega pixels, file size, image size, and print size - Adobe Evangelists | Frank ess | Digital Photography | 0 | November 14th 06 06:08 PM |
Help with image size before taking image to printer. | Mr. Rather B. Beachen | Digital Photography | 5 | July 4th 04 04:23 PM |