qiang_lin

You have 5x4x4800^2=460,800,000 pixels. If you use 16bit depth then there are 6 bytes for each pixel, thus you get 2,764,800,000 bytes per immage. I don't think this size is trivial.

The true question is: do you have enough RAM and storage on disks to save the huge file you are going to produce? Even if you do, is the software you are going to use capable to deal with it? You can calculate the number of pixels you are going to get, then multiply it by the number of bytes each pixels uses to figure out what I mean. I don't think you ever need the max resolution for even 120, not to mention 5x4.

The camera store on Lake Ave called "Mac Lee's Camera" (if my memory is correct) may have some. It is on the east of Macy's.

"All lenses at the same F stop,have the same DOF regardless of focal length,providing the image size is the same."

 

Sounds strange. Bob Atkins has a good article, although it's title is "Depth of Field and the Digital Domain", I think it is quite helpful. There is a formula that explains everything, at least to me.

Try http://www.photo.net/learn/optics/dofdigital/

As many of you have experienced with prints, I got my films scanned with half frame and half of the next by Snapfish. When I complained to their customer service, I was suggested to calibrate my monitor and printer! I didn't know that could solve the problem!

It will take quite a while for the full frame sensors to be afordable. The size of such sensors is bigger than the CPUs in your PC or Mac. The processing speed is much higher than the general purpose CPUs, meanwhile the power consumption is much lower. The day when PCs can alter your photos at a speed of 4fps have a price around 1K$, DSLRs with full frame sensors will be afordable. Keep waiting...

Maybe you can simply Zip your file. It preserves whatever in your original file, but requires Un-Zip before you open the compressed file. It's pretty common to Zip files at least among engineers, since we have all kind of different file formats and not all of them have the compression capability. There are several freeware that do this job pretty well.

One more point. Most modern digital equipments have very high digital noise internally, and most of them use switching regulators in side, which will introduce quite a lot of noise. On the other hand, Hi-Fi world use pure analog circuitry. As you can see here, since there are so much noise generated inside the equipments, it doesn't make much sensor to further filter the power supply. Well designed equipments can deal with noise generated internally so that they can have reasonable performance.

As an Electical Engineer, I totally agree with Joe. A well designed product should have enough filtration and rejection inside. The super expensive cables I used at 20GHz are not meant for audio use. Cables with lower frequency response actually provide extra filtration which in most of cases will help the overall performance. Even the military projects will decline this kind of waste of money. As for UPS, it makes voltage stable, but since most UPSes are build by DC-AC inverter, the noise level (not to be confused with surge) may be high. If you want cleaner power, this may not be a good choice.

I feel even more annoyed than Peter, cause I just ordered Dual 3 days ago. I went to Minolta's Japanese web site to check the information. Interesting is that they said measured Dmax is 3.6. This is the first time I found any manufacturer announces measured Dmax instead of some numbers based on some inaccurate calculations.

I shifted from Nikon FE to Elan 7E. I love FE, but Elan 7E's eye control auto focus is great! I fell in love with it the moment I started to use it.

I think Alex is right. With finite number of samples (pixles), random noise is not really random with zero mean as we assumed. Any filtering will make this (non-zero-mean) more noticable in a form a another because the result is less noisy.

Goto ezShop on this web site. Several memebers have used this Sigma lens. Check out what they say.

Neal explained physics very well here. What makes things more interesting is that if the lens has a higher resolution than the sensor does, the lines resolved by the lens may cause "aliasing" in the sensor, which will introduce wierd things in the image. This is why they have anti-aliasing filters in front of the sensors in some high end digital backs. With this filter or not, the resolution will always be reduced by either aliasing or the filter. I am not saying that you don't need good lenses, but just want to remind you that top of the line optics may not give you the result as you expect.

I couldn't find the article. But a lot of Yashica cameras were carrying Kyocera name in many Asian countries including Japan when I was there. If they only change the name, what is the difference? If they kill some of the non-profitable product lines, may be a bad news for us, but it is understandable, isn't it? They have to survive in this world.

Marc, there are several reasons.

<ol>

<li>Most flatbed scanners do NOT have the resolution as they claim.

<li>Most if not all flatbed scanners do NOT have the ability to adjust the focus. This is one of the resons why they can't achieve the resolution as I stated above.

<liThe sensor and the ADC may not have enough dynamic range to capture your images on the film. They are good engough for scanning prints, which, by the way, you don't need that much resolution (300 dpi/ppi should do the work).

<li>It makes engineering easier if you optimize for one particular target, i.e. scanning film in the case of film scanners. There are a lot of thing to be worried for the engineers designing large flatbed scanners so they have to compromise.

</ol>

I haven't used it by myself, but here is a good review on a wood tripod. http://www.photofocus.com/zine5.htm

If you go to http://www.popphoto.com , you can find test reports on Tokina, Sigma and Tamron, all in this focal length range. It seems that Tamron is better in performance.

According to Pop Photo, this Tamron is way better than the counter parts from Sigma and Tokina.

Agree with Arthur and Vandit. If you get the prints from a drug stroe or a super market, you won't get sharp results no matter how perfect your shots and equipments are. The machines are not tuned to give good quality but to maximize the throughput. My snaps from a digital P&S were much better than any photo I got from films, becuase they don't suffer from the terrible scan in those machines. But this doesn't mean my equipments are not as good as the digital P&S.