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Francoflier
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Digital Camera Question...

Mon May 12, 2003 1:54 pm

Hi all!

This topic has probably been extensively and thouroughly looked over in previous threads, but I only recently became interested in the photography techniques, so here goes:

I understand a digital cam's resolution is expressed in terms of megapixels. I realise there are many other factors of "performance", one of them being the person pushing the button, but apparently it always comes down to those megapixels...
1/ From about how many megapixel can a digital cam bear the comparison with a 35mm cam (say a not so bad one)?

2/ How many megapixels would you need to have enough resolution to, say, have your shot accepted in the A.net database through its very critic screeners, for instance?

I meant "very critic" as a compliment to the very high quality of the pictures contained in this database!

Thank you for any bit of help!
Regards,

Francoflier.
I'll do my own airline. With Blackjack. And hookers. In fact, forget the airline.
 
jwenting
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RE: Digital Camera Question...

Mon May 12, 2003 2:36 pm

I understand a digital cam's resolution is expressed in terms of megapixels. I realise there are many other factors of "performance", one of them being the person pushing the button, but apparently it always comes down to those megapixels...
That's indeed what many people want you to believe and it's quite incorrect!
The resolution in megapixels does only define the MAXIMUM amount of useful data the camera can record.
What is also important is the size of the CCD (if I cram 5 million pixels onto a 1 square centimeter surface I'll be able to record far more detail than when I put the same pixels onto a 1 square meter surface).
Vitally important (as with every camera) are also the optics that produce the image onto the CCD.
You're better off with a 3MP camera with great optics than you would be with a 6MP camera with crappy optics.

1/ From about how many megapixel can a digital cam bear the comparison with a 35mm cam (say a not so bad one)?
For small prints (up to say 10x15cm) a 3MP camera will produce about the same quality as a 35mm camera with the same optics.
On a computerscreen, blown up to 1024x768, you want at least a 3MP camera, preferably 5MP.
For enlargements of say 30x45cm, you're looking at 10MP and more.

2/ How many megapixels would you need to have enough resolution to, say, have your shot accepted in the A.net database through its very critic screeners, for instance?
Some people are using 3MP cameras, but they usually have the very best cameras with excellent lenses.
Those cameras that fit that description and are still in production usually have 5MP or more now.
I wish I were flying
 
ckw
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RE: Digital Camera Question...

Mon May 12, 2003 6:01 pm

I think these days how the data is processed is as important as sheer pixel count - cramming more pixels onto a CCD introduces problems (noise, blooming, colour shift etc.) and a lot of black box activity is required to address this. Ultimately you want as clean an image as possible to allow for poat processing and enlargement. Hence the D30's relatively low 3.3mp can still produce higher quality images than many of the consumer 5mp cameras.

Another factor to consider are the handling - a major headache for many with aviation photography is shutter-lag - even high res consumer cameras may have a noticable delay between pressing the shutter and the image being captured.

Cheers,

Colin
Colin K. Work, Pixstel
 
paulc
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RE: Digital Camera Question...

Mon May 12, 2003 6:47 pm

Colin,

agree with you re shutter lag - most digitals (well mine anyway) is ok for GA in flight shots as they are relatively low speed. Airlines on approach are difficult and fast jets are not even worth trying to shoot.

regards
Paul

ps - did you get to Kemble over the weekend??
English First, British Second, european Never!
 
jwenting
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RE: Digital Camera Question...

Mon May 12, 2003 9:19 pm

Colin, of course postprocessing is important. But the question here was about the camera hardware as I understand it.
The main reason a D30 produces a better image than your average consumer P&S is the fact that most D30 users will have some high-end glass lenses on it instead of a shitty plastic "lens" smaller than a fingernail.
Compare a D30 with mid-range lenses to a high-end prosumer 5MP camera like a Coolpix 5700 or Dimage 7i and you're unlikely to see that much of a difference in optics while the D30 will still have less resolution.
You're quite right that there is a limit to the sensordensity that can yield useful results (within the restrictions of each sensor generation) and that some cameras might be designed with a higher density than that for marketing reasons alone.
I wish I were flying
 
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Francoflier
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RE: Digital Camera Question...

Wed May 14, 2003 12:11 pm

Thank you all for the answers!

Wow, that stuff is definitely more complex than I thought.
I'll do my own airline. With Blackjack. And hookers. In fact, forget the airline.
 
gmonney
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RE: Digital Camera Question...

Wed May 14, 2003 1:11 pm

If you are looking for the point and shoot and let the camera do all of the work, I couldn't be more happy with my Sony F717, its 5MP (which as we all read above is good) it has 5x optical zoom and it only gets better with a converter, and the features allow for more time taking pictures than not. A friend has a D30 and he is amazing and a great photographer, way out of my league, so that camera suits him. IF you are like me and just want to Point, Shoot, Upload and enjoy on a.net, go sony if you can!

Grant
Drive it like you stole it!
 
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clickhappy
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RE: Digital Camera Question...

Wed May 14, 2003 1:41 pm

the downside to a Sony is the proprietary memory stick system, and the fact that the largest size available is 256 megs.
 
ckw
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RE: Digital Camera Question...

Wed May 14, 2003 5:32 pm

But the question here was about the camera hardware as I understand it.

I think you mis-understood my reply - I'm not referring to post-processing (as in what you do to the pic afterwards) but the on-camera processing that occurs as you take the shot - very much an integral part of the camera, and IMHO the factor which differentiates most camera's image quality. The filtering and processing done by the camera is responsible for a) the apparent sharpness of an image b) the management of noise and c) colour fidelity.

If you think of resolution in terms of useful data as opposed to all data which includes noise, a noisy 5mp camera will have a lower effective resolution than a clean 3mp camera. You can see the effect more clearly if you compare slide scans to digital - a good scanner may produce an equivalent 25mp of data, yet image resolution is nowhere near 4x as good as a good 6mp DSLR - 4x larger, yes, but with a lot of noise and less sharpness.

Pixel counts is not the best way to measure image resolution (anymore than is counting grains on film) - it is only a guide to the maximum potential resolution. All cameras "waste" some of that potential - the on camera software (plus any antialiasinging filters) determine how much, and this varies considerably. Image resolution is correctly measured by line pairs per inch (lpi), that is, the max density of lines which can be individually distinguished on an image - unfortunately, this is a subjective measuremnt to some extent, so can't be used as a basis for scientific comparison.

Cheers,

Colin

[Edited 2003-05-14 10:33:13]
Colin K. Work, Pixstel
 
gmonney
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RE: Digital Camera Question...

Thu May 15, 2003 5:24 am

Well when it comes to picture capacity on the memory stick, if you can fill one or two Memory sitcks, I get over 100 pictures on my 128MB stick you will have to just keep your finger on the shutter button all day, AND i take pics at 2048x1536, for me thats large enough and when you size them down to a.net specs, it work out perfect!!

That is my honest opinion!

Grant
Drive it like you stole it!
 
mikephotos
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RE: Digital Camera Question...

Thu May 15, 2003 5:34 am

2/ How many megapixels would you need to have enough resolution to, say, have your shot accepted in the A.net database through its very critic screeners, for instance?
Some people are using 3MP cameras, but they usually have the very best cameras with excellent lenses.
Those cameras that fit that description and are still in production usually have 5MP or more now.>


I've had several shots from my 2.1MP super-compact digital accpeted.

the downside to a Sony is the proprietary memory stick system, and the fact that the largest size available is 256 megs.

Will some of the newer Sony's accpet the 512MB and 1GB MemoryStick Pros?

Mike



 
BHXviscount
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RE: Digital Camera Question...

Thu May 15, 2003 8:42 am

interesting stuff Colin(ckw)... on the subject of the D30 v 5700coolpix/dimage 7i which in terms of image quality is it best to go for? have not GONE digital yet but am going to make the leap soon.
One thing that I don't understand is on uploading to A.net it is at 1600pix max so if using 3meg camera thats larger, how do you resize the image without losing quality??
No officer, its NOT a surface to air missile its a camera..for taking photographs.

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