megapixels

[dgfassett]

A 35mm format Nikon DSLR has 10.2 mp. Would a Hasselblad have the same

resolution,or four times greater, since it is about four times larger?

[ellis_vener_photography]

numebr of pixels is not tied directly to resolution.

 

How large are you planning on printing?

[leicaglow]

The newer Hasselblad stuff is generally 20-40Mb, but Ellis is right; there's more to it than Mp's. The other backs have 16 channels, I believe, while the D200 is 12.

[photo5]

I've found that internal image processing is just as important as the number of megapixels. I've worked on images from medium format digital backs that were pretty ugly. Granted, they are ugly because the photographer tried to make the image look better before we received it.

 

Ellis has the right question. What is your desired output size? You'd be surprised how large a print you can make from a 10.2mp Nikon dSLR. A friend of mine routinely makes 20x30" prints from his D200 with no issues at all. I've only made 13x20" prints from my D80 so far, but they look amazing.

 

Dave

[tonybeach]

Dennis, there is no current Nikon DSLR using the "35mm format", they use a cropped version which is the DX format. Resolution is resolution, but if the sensor is larger than it doesn't need to be enlarged as much, and that is a separate issue that has implications for acuity in larger prints when more enlargement is required.

 

Michael, I'm pretty sure you meant 16 bit color depth versus 12 bit color depth; the D200 and D2x use 4 channels to move data off the sensor and through the ADC while the D80 and D40x use 2 channels. Nobody uses more than 4 channels.

 

Regarding the difference between 12 bit color depth and 16 bit color depth, that is the difference between 4096 levels for 12 bits from the highest EV and the lowest one and 60,000 levels for 16 bits. If you shoot compressed RAW (which the D40, D40x, D50, D70 and D80 are limited to) then you are actually only using 10 bit color depth. JPEGs are 8 bit color depth and just exceed the human eye's ability to discern anything but a smooth tonal ramp unless you stretch the tones with curves. Fuji uses 14 bit color depth in their S3 and S5 cameras, and the price is 25 MB files when shooting at the highest DR.

[dgfassett]

I am relatively new to digital. While I have extensive professional experience with film, Some components associated with the digital collection and recording of images seem to have little in common with film. I have several relatively new digital DLSR's including a D200 as well as many old, but still good, film machines. Prior to digital, you would not have found many professional photogs shooting weddings with 35mm. However, correct me if I am wrong, it seems that today, many are quite happy with results delivered via a D200 or even 6mp machines. It seems counter intuative that larger 2 1/4 formats would not remain the most desireable. Perhaps it is indeed only the size of the final print that determines the equipmnent used. Why then, are there still digital medimum format cameras still being produced?

[frans_waterlander]

Dennis,

 

MF digital cameras have the potential to deliver superior, large prints. These cameras are also prohibitively expensive for most people. While you pay thousands of dollars for good dSLR's, you pay tens of thousands for MF digital cameras.

[tonybeach]

Theoretically there is no limit to how much you can enlarge film, however in practice it is limited by the film's grain. The grain of a film emulsion is the same regardless of how large the format you are using, but smaller formats have to be enlarged more than smaller formats and the grain therefore becomes noticable sooner with smaller formats.

 

Digital resolution on the other hand is limited by the point at which the pixels become visible. If there are more pixels packed into a smaller format than those pixels will have to be enlarged more before you can see them; but then the biggest issue becomes diffraction as the CoC (circle of confusion) starts to overlap one or more bordering photosites and this will cause the image to become noticeably blurry as it is enlarged. A secondary issue that is similar to film is noise, and when all things are equal (and they never are) larger photosites will have less noise than smaller ones.

 

For both film and digital the larger the format the longer the focal length to get the equivalent FOV (field of view). This has several implications related to IQ (image quality). Longer focal lengths magnify more than shorter ones and therefore are capable of more detail. Longer focal lengths are less compromised than shorter ones when it comes to distortion. Using the same aperture on a larger format with a longer lens to achieve the equivalent FOV provides a shallower DOF (depth of field). Often overlooked is that the CoC outside of the theoretical DOF increases faster at longer focal lengths than it does at shorter ones, which is why longer focal length lenses have better bokeh than shorter focal length lenses.

[mvtol]

I believe this is the "cheapest" MFD at the market at the moment. If you already have Mamiya AF lenses, the price is still steep but when you work as a professional...

 

http://www.dpreview.com/news/0509/0509094leaf_mamiya22mp.asp

 

regards,

Martijn

[ellis_vener_photography]

In good light, A human can make out approximately 9 bits per red , green and blue channel

[calebcondit]

well, if you live in europe, you can get a 22mp mamiya zd for about 12k.

[dgfassett]

Thanks to everyone for your responses. However, if as has been stated, that the primary function of a collection of organized megapixels is to simply record an image closely representative of that small slice of reality upon which the D200 was aimed, then why would anyone need more megapixels than required to accomplish that task. It has also been stated that 10mp will provide very good reproductions at the level of an 8x10, why would anyone not needing prints larger invest in additional capability? Perhaps I am missing something. I was once advised by several lens manufacturers that the greatest therotical lens resolution was 750 line pairs per millemeter. How does that number equate with this discussion of megapixels?

[tonybeach]

One reason for extra megapixels is to allow for cropping, which can be very useful if you are using prime lenses. I have also found it very useful with my D200 to often just take pictures in landscape orientation and to simply crop to portrait orientation, which make perfectly adequate 8x10 prints. Another reason is that having extra megapixels doesn't preclude the option of making larger prints.

 

I doubt anyone could tell the difference between an 8x10 print from a 6MP DSLR and a 10MP DSLR, but you will be able to see the difference in a 16x20 if you look closely. Many in this forum report getting very large prints from their 10MP cameras. The problem with putting any more resolution into that small a format is that the currently available lenses are not good enough to give you any extra benefit. This is one reason many are clamoring for a 35FF sensor.

 

A 10MP DX sensor equals 82 lppm, which actually exceeds nearly every lens in the Nikon line-up. However, the anti-aliasing filter and Bayer filter array reduces the effective resolution. FWIW, my D200 can clearly distinguish between the best available lenses and I can even tell you how they perform at different apertures.

 

If you have the money to spend, then you can purchase a 39MP digital back and some very expensive lenses that will match up to it. You ask "why not?", and the answer is twofold. First, the price will be about the same as a luxury car. The second is that MF digital backs are cumbersome, slow, eat up a lot of memory, and even wealthy photographers are reticent to use them in harsh weather. There is an increasingly popular alternative to this, and that is to use a more modest DX or 35FF DSLR, take multiple shots using a Panohead, and then stitch them together when you want a monstrous amount of resolution.

[dgfassett]

Thanks again Anthony/

[dgfassett]

Off the subject. How long will a thread such as this remain available for browsing?

[tonybeach]

You're welcome.

 

I cannot say how long the thread will be available for browsing, but it is cached and will be in your history for years to come.