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A rumour but then I have been right twice before

Marc,

Try res&ling something that yields less than 300dpi and then compare. Your printer is just throwing out anything over 300 dpi anyway. It's when you're less than 300 dpi that any difference, if any, should become evident.

Guy
 
>

I've exchanged a few missles with Austin in the past, and maybe I missed an item in this thread, but I think he's been nothing but polite and helpful in this thread and I've learned a bit from his responses. Austin, when you become the topic of the thread, for better or worse, you've arrived baby!

Chip

>
 
Guy,

> Try res&ling something that yields less than 300dpi and then > compare. Your printer is just throwing out anything over 300 dpi > anyway. It's when you're less than 300 dpi that any difference, if > any, should become evident.

That depends on the printer. The Epson "desktops" res&le up to 720 prior to doing the dithering algorithm. Now, whether the data is useful or not, that is very image dependant...but at least for the Epson desktops, it's not simply "thrown away". With the Epson large format printers it's 360...

Regards,

Austin
 
Austin,

Do you know for sure that the Epson drivers work on a physical "dither cell" resolution of 720ppi? Is that what they actually deliver to the paper? I understood that the algorithm was more complex than that?

What I do know for sure is, if I scale an image for print at 300ppi, then I can *just* see the jaggy with my naked eye on a hard diagonal boundary. It's most obvious when a primary colour is involved, e.g, on a portrait I took recently where the subject is wearing a red long-sleeve sweatshirt with white sleeves. The edge between the sleeve and the red part of the shirt has the same look that I remember from text on 300dpi laser printers back in the day. This is with fairly mellow sharpening settings. If my eye can see that, surely it's warranted to use a finer-res file if possible.

-= mike =-

PS. C'mon Marc, play nicely now!
 
Hi Mike,

> Do you know for sure that the Epson drivers work on a physical "dither > cell" resolution of 720ppi? Is that what they actually deliver to the > paper? I understood that the algorithm was more complex than that?

Dithering does not have to be fixed size cell based, it can be random/stochastic as I believe the standard Epson dither pattern is these days. What the driver delivers to the paper is printer dependant, and direction dependant. Some of the printers are 1440 in one direction (720 in the other), and some are higher...2880. The algorithm is more complex than simply ups&ling to 720, if that's what you thought I meant, it's not. I only said that the driver ups&les to 720 BEFORE running the dithering algorithm.

> What I do know for sure is, if I scale an image for print at 300ppi, > then I can *just* see the jaggy with my naken eye on a hard diagonal > boundary.

Interesting...you must have "loupe" eyes ;-) How close are you looking to see this?

Regards,

Austin
 
Hi Howard,

> As I understand you, the source of the display that is in back of the > digital camera is not from the 5mb pixels, 6mb pixels, 11mb pixels > sensor in which the digital image is taken, but from a separate > interline sensor.

That could be on some cameras, but I'm unaware of any that do it that way. The DSLRs don't have real-time display (on the display on the back that is), because of the issue with the mirror being in the way of the sensor, and because the sensors require the use of a shutter.

> At present, the interline sensor has real time > update problems, and sharpness issues making it difficult or > impossible to manually focus photo's.

Agreed. The image quality of interline sensors is too low, and the update too slow, IMO to use for manual focus.

> As far as having no display when shutter is closed no display, doesn't > the same thing occur with any SLR, when the shutter is depressed, the > mirror swings up out of place the subject can espose either the film > or sensor media. Or are you referring to something else?

If I understand you right, they are not really the same thing...because your optical display works all the time except when the mirror is flipping/flipped up...and a digital display, working only when the shutter is open, and the shutter only opens when the image is being "taken", means the image sensor can't be used for producing a real-time digital display.

This MAY be able to change at some point in time (it, IMO, requires a change in the sensor design, and obviously, in the camera operation as I'll describe), where the shutter can be opened, display info taken from the image sensor, then the shutter closed when the image is to be taken, shutter opened for the exposure time, then closed again while the image is read out...but...this, obviously, adds the lag time of closing the shutter to the exposure equation...but...I think that might be easily done at the same speed as it would take for the mirror to flip up, aperture stop down...so I'm hopeful that may very well work OK. There is also work being done with non-mechanical shutters, that are purely optically based, but they don't get dark enough, and aren't fast enough right now, at least the ones I've used/heard of.

> I am not technical person like you so please explain everything in as > simple terms as possible.

You seem to be doing quite well.

Regards,

Austin
 
Hi Austin,

Yeah that makes sense. Now I see why people say that 360 and 240ppi are good figures to aim for when scaling for output. From what I can tell, it's tricky to actually get the right ppi out to the page from Photoshop, because there seems to be a difference between the printable area reported by the driver and the final printable area on the page. Because of this, I have just been scaling to get the crop I want, and hoping there are enough pixels that the end result is smooth. With the Minolta 5400, there are plenty of pixels
happy.gif


I can see the jaggies from a fairly close inspection distance, where I hold the print up and make an effort to judge it. Probably around 10" distance on average. I can't quite make them out in normal viewing at "hand distance" but once I know they're there it's tempting to think I can still see some roughness, but that may be psychological. I've been very lucky with my eyes, the last time I had a test about 2 years ago I was told my vision was 60/60, which sounds impressive although I don't really know what it means ;o)

TTFN

-= mike =-
 
Austin,

I appreciate you taking the time to explain the current technology relating to LCD's, and demonstrate that they are far from being capable of replacing mirror pentaprisms in DSLR's at this time. I believe that at some future time (measured in years), engineers and innovators like yourself will solve the current deficiencies in design and technology and bring to market cameras that are smaller, lighter, more capable, have better features, and are able to produce better photographs, more easily. Maybe they will have features which will prevent guys like me from playing with all those dials and buttons, because I think I can do a better job than the camera -- which usually I cannot.
Thanks again,

Howard
 
Nikon D2H has just come out, and looks like Nikon is trying to standardize the 1.5x crop ratio (or whatever it is called) as the "DX format." I wonder what the next Contax offering will be like in terms of its frame size...any more news Simon?
 
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