Comparison of 4 film formats and 2 digital cameras

[Jorge Gasteazoro]

He then takes this flawed basis -- he assumes that the quality level of the 300D is representative of all digital cameras (it isn't) -- and extrapolates flawed conclusions from there.



Correct me if I am wrong, but isn't the 300D a middle of the road camera most likely to be used by a non pro? Isnt this camera with the lens that comes with it an equivalent of the Canon 35 film camera?



I find this objection curios, because with a 35 mm film camera the body does not matter, sure some bodies can do double exposure etc, but the body is in most cases unimportant. Are you telling me that if I want to take digital pictures that can equal the quality of a run of the mill 35 mm slr I have to go and buy special lenses and a top of the line pro camera? This does not make sense to me.

[Richard Fenner]

May I inject a small note of criticism? I have a horrible time when it comes to using numbers in different contexts - you should see me shake when I use stats packages! But, it seems to me, when I look at the bottle shots, taking the 6x7 image, I'm looking at it as if it was taken from a print approximately 3m by 3.5m (a bit shorter, as 6x7 isn't 6cm by 7cm). For the 8x10 and 4x5, as if they were 3.12m by 2.5m (the changed degree of enlargement in the image presented accounts the format differences, so they're effectively the same size). Previous comments on this site indicate a MAXIMUM normal print size for most people to be about 1.25m by 1m (50x40) - 40% of the enlargement shown. It would seem to me, to be meaningful at a print size of 50x40, the images shown would have to be reduced by 60%. For the people who typically make even smaller enlargements, (and from recent threads, this is the majority), an even greater reduction would be required.

In short, 50x is predisposing the results to be those we would like to see - the greater the magnification, the larger formats must by definition win, regardless of the real-world ability to discern a difference in prints on the wall (which I take to be 'real world' - others may have different criteria).

Or have I blundered with the numbers?

Richard.

[Bill_1856]

I do not believe that the results, as published, represent an accurate comparison of the best (or even the usual) results obtainable from these diverse media.

[Darin Cozine]

Yes there are a few problems with this comparison.

The LF equipment was tested with top-of-the line optics. Meanwhile the digital cameras and lenses were entry-level. I have seen another test which compared a Canon EOS 1d 12mp with its counterpart EOS-1n. The same L-series lens was used, and various films were tested. The film was scanned with various methods and a microscope with a digital camera.

The plaubel Makina has performed poorly in other tests due to a misaligned rangefinder. A Mamiya 7 or Hasselblad would perform much better.

[Bert Otten]

To give some short answers:

Ellis,

if you see the captions under the USAF charts: raw files were used of the digital cameras, so I did state that.

I used the 300D as a representative of a good 6.3 Megapixel camera and showed that there is quite a big difference with a 5 Megixel compact. I did not extrapolate anything to other digital cameras: If you look in my Printsizes part, I put question marks behind my calculations of a 14 megapixel digital camera, because I can not be sure.

I did include the data read from the film directly before scanning (indicated by “original” in the tables), so I have not only tested the scanner, although I did state that the scanner was the weakest link. Today I have looked with a microscope at the air image of the plastic lens of the Canon (18-55) at the same focal length setting as in the test and seen that on axis the image of the USAF chart is resolved with the finest detail blocks at full opening of the lens. This implies that the lens has a resolution of a factor of at least 2.5 times higher than the test result of the whole camera. The lens was not limiting.

Ellis, I think therefore my testresults are useful, since I have answered all your points of criticism. Thanks for your input.

Richard,

Yes, the format of the film largely determines the printsize possible that is still sharp to the human eye at reading distance. The beer bottles represent different amounts of magnification, indicated under the images. The point is: If I would like to print the presented scene from all cameras and formats on the same size, what can I expect? Finally, my table of maximal printsizes is a practical upper limit that is handy when you prepare an exhibition

Bill,

It is hard to answer criticism that contains no arguments. “Believing” is not part of experimental science, only a start of doing experiments.

Darin,

I have aligned the rangefinder of the Plaubel Makina, and if you look at the numbers, the film shows a resolution of 55 linepairs/mm in the filmplane, which is the same as the results in the other large cameras. Given the time, I will repeat the experiment with a Hasselblad, but I don’t expect wildly different results.

Thanks very much for your time!

[Ellis Vener]

I find this objection curios, because with a 35 mm film camera the body does not matter, sure some bodies can do double exposure etc, but the body is in most cases unimportant. Are you telling me that if I want to take digital pictures that can equal the quality of a run of the mill 35 mm slr I have to go and buy special lenses and a top of the line pro camera? This does not make sense to me.

let's use the automobile as a metaphor . The engine and the chassis of a digital camera are the sensor array that converts the photons that strike it nto sanalog signals which are then processed into a digital signal (zeros and ones). The camera body as you are thinking of it -- chassis, meter, lens mount, shutter, etc. is mostly irrelevant to the extent that they don't interfere with the quality of that process. You can put a 250 hp engine and aterific transmission in any car and it will go like a bat out of hell (for awhile). Similarly you can but a Yugo engine and transmission in a Corvette or BMW and turn the car into a chump. You can also take a good sensor array (the CMOS or CCD "chip") and then use a variety of firmware & software programming, as well as processing hardware to get different kinds of results. Sort of like mixing a BMW engine, and then your choice of transmission. So to be more precise, when I say "digital camera" I am referring to the quality of the camera's digital drive train , all aspects of which to a greater or lesser degree have an effect the quality of the image.

Lens quality is an undeniable factor in the quality of image making whether we are discussing digital or film based photography. In general digital cameras do need higher quality lenses than film based imaging requires. This is because ofthe different mechanical nature of the two types of medium. Put a medium quality of lens on the front of a digital camera and you limit the quality of the output. The immutatable rule of computation is "garbage in, garbage out."

With digital imaging you are not justthe photographer but you are the lab too. if you choose to use a "raw' capture mode you are also to a large degree the "film" manufacturer as well. And atthat point it comes down to how you process the image and the tools you use to do the processing with. Any version of Phase One's Capture One DSLR "raw conversion" software is more powerful than Canon's (as is Adobe Photoshop CS); even more powerful is the full version of Capture One (and in some areas it is even more powerful than Adobe Photoshop CS). The strength and quality of a digital imaging program are the algorithms used to translate the digtal signal back int oa visual form.

Otten does nt specify how the digital images --scans or direct in camera capture - were processed. 8 bit? 16 bit? Jpeg? Raw? Tiff? What software was used? what kind of sharpening was used (all digital images require sharpening), etc. , so basically all Mr. Ott is doing here is comparing results from a low to mid quality desktop scanner against the results of a low to moderate quality digital SLR against a low quality point and shoot camera. For all of these reasons, these tests really don't prove anything except that 8x10 & 4x5 film have highr resolution that smaller formats.

But more power to Mr. Ott for actually doing some sort of testing himself as opposed to just accepting other people's words at face value. He deserves (and gets from me at least) a lot of respect for doing that.

[Ellis Vener]

I find this objection curios, because with a 35 mm film camera the body does not matter, sure some bodies can do double exposure etc, but the body is in most cases unimportant. Are you telling me that if I want to take digital pictures that can equal the quality of a run of the mill 35 mm slr I have to go and buy special lenses and a top of the line pro camera? This does not make sense to me.

let's use the automobile as a metaphor . The engine and the chassis of a digital camera are the sensor array that converts the photons that strike it nto sanalog signals which are then processed into a digital signal (zeros and ones). The camera body as you are thinking of it -- chassis, meter, lens mount, shutter, etc. is mostly irrelevant to the extent that they don't interfere with the quality of that process. You can put a 250 hp engine and aterific transmission in any car and it will go like a bat out of hell (for awhile). Similarly you can but a Yugo engine and transmission in a Corvette or BMW and turn the car into a chump. You can also take a good sensor array (the CMOS or CCD "chip") and then use a variety of firmware & software programming, as well as processing hardware to get different kinds of results. Sort of like mixing a BMW engine, and then your choice of transmission. So to be more precise, when I say "digital camera" I am referring to the quality of the camera's digital drive train , all aspects of which to a greater or lesser degree have an effect the quality of the image.

Lens quality is an undeniable factor in the quality of image making whether we are discussing digital or film based photography. In general digital cameras do need higher quality lenses than film based imaging requires. This is because ofthe different mechanical nature of the two types of medium. Put a medium quality of lens on the front of a digital camera and you limit the quality of the output. The immutatable rule of computation is "garbage in, garbage out."

With digital imaging you are not justthe photographer but you are the lab too. if you choose to use a "raw' capture mode you are also to a large degree the "film" manufacturer as well. And atthat point it comes down to how you process the image and the tools you use to do the processing with. Any version of Phase One's Capture One DSLR "raw conversion" software is more powerful than Canon's (as is Adobe Photoshop CS); even more powerful is the full version of Capture One (and in some areas it is even more powerful than Adobe Photoshop CS). The strength and quality of a digital imaging program are the algorithms used to translate the digtal signal back int oa visual form.

Otten does nt specify how the digital images --scans or direct in camera capture - were processed. 8 bit? 16 bit? Jpeg? Raw? Tiff? What software was used? what kind of sharpening was used (all digital images require sharpening), etc. , so basically all Mr. Ott is doing here is comparing results from a low to mid quality desktop scanner against the results of a low to moderate quality digital SLR against a low quality point and shoot camera. For all of these reasons, these tests really don't prove anything except that 8x10 & 4x5 film have highr resolution that smaller formats.

But more power to Bert Otten for actually doing some sort of testing himself as opposed to just accepting other people's words at face value. He deserves (and certainly gets from me) a lot of respect for doing that.

[Ellis Vener]

I was busy responding to Jorge while Bert was responding. I double posted because I realized I was spelling "otten" Ott in at least (and hopefully only) one place.

[Bert Otten]

Ellis,

that's a good point: I only indicated that I used RAW as file format for the digital cameras, but not how I processed them. Neither did I include information on the color depth of the scans or sharpening. I will add that to the site. For now I can say that I did all I could to get the maximal resolution out of the digital files, so 16 bit, the Camera plug in of PhotoShop CS, in which I used the chromatic aberration correction option, but not the noise reduction. For the scans I only sharpened in PhotoShop at the 1 pixel level to 100%, to avoid any unwanted overmodulation, but to be shure I got the limit of resolution. So thanks Ellis, I will add the information to the site.

[John Kasaian]

Very enlightening! I won't be trading my 'dorff for an elph(but the thought never really crossed my mind anyway!)