Digital Pics on HDTV vs Analog Slide Projection

[photo_color]

I was thinking of scanning my 35mm slides at high resolution,

putting them onto DVDs, and then, eventually showing them on large

screen HDTVs. Also, thinking of buying a digital camera, and showing

the results on the same TVs (i.e. when the prices come down I can

buy say a 60" plasma or whatever technology offers the best

picture). Over time these large screen HDTVs will become more

prevalent, and I could do away with a slide projector.

 

However, I've run into a snag, at least theoretically. The HDTVs

seem to be limited to about 1366x768 pixles (50-60" plasmas). Even

if the resolution increases with other technologies, even a 'lowly'

4mp camera can deliver 2272x1704. So, am I missing something? I

won't be able so see the full resolution of pic taken with a 4mp

camera on the current crop of 60" plasma HDTVs? The full resolution

of the pic would only come into play enlarging sections of the

pictures on a computer monitor, or making large prints ?? If so, I'm

going to stay with my 35mm slide project a lot longer than I thought.

Thank you.

[lotsawa]

There was an interesting and detailed article on digital vs. analog "slide" projection in the German computer magazine "c't". The comparison was between beamer and a slide projectors not between HDTV and slide projector. Sorry, my English far from good enough to describe its contents adequately, but I'll try anyway to report a bit of it ...

<p>

There is formula with which you can calculate the minimal distance between the viewer and the picture that is necessary so that the human eye can't see individual pixel of the picture any more, in other words, the picture appears sharp. Here is a table of that article with results of such calculation:

<p>

<table border="1" cellspacing="0" cellpadding="2">

<tr><td>

resolution <td> ratio <td> pixels of the diagonal <td> optimal viewing distance* </tr>

<tr><td>

SVGA 600 x 800 <td> 4:3 <td> 1000 <td> 2,3 m </tr>

<tr><td>

XGA 1024 x 768 <td> 4:3 <td> 1280 <td> 1,8 m </tr>

<tr><td>

SXGA 1280 x 1024 <td> 5:4 <td> 1640 <td> 1,4 m </tr>

<tr><td>

SXGA pro 1400 x 1050 <td> 4:3 <td> 1750 <td> 1,3 m </tr></table>

(* calculated for a size of the projection of 120 cm x 90 cm)

<p>

That actually means for the best quality picture out of this table, the one projected by the beamer with 1400x1050 pixels, you really need only about 1.5 MPixels!

<p>

With the beamers they tested, the picture looked very bright, with high contrast, and also sharp if you keep the suggested distance. If you go nearer, you see the pixels, that means the picture becomes unsharp. In this respect the slide is much better. The beamer's colors are a bit 'cooler' and brighter, those of the slide projector 'warmer'.

<p>

A weak point of the beamer is the lesser ability to show details in dark areas (shadows). The subtle gradations in the shadows are shown a bit less. You need to calibrate the beamer well. Also, depending on the structure of the picture (if it has fine structures), there is a tendency towards moiré.

<p>

The bottom line is that digital projection reaches high quality with beamers with a resolution of at least 1024x768. Even better results were produced with JVC's DLA-SX21 that has a resolution of 1400x1050.

<p>

With the possibilities of creating a real good 'slide-show' that you'll have on the computer useing software like ScreenAV, the digital technology might replace the traditional slide show to a large extent.

<p>

Hope that helped a bit!

[jon_austin]

You are correct. My CRT-based HDTV's highest resolution is 1080i, or 1920x1080 interlaced.

 

But I've been using this set to display slideshows of my digital pics for over two years now, and it looks simply fantastic. The display is driven by a PC dedicated to this purpose (home theater PC), which is equipped with an ATI All-In-Wonder video card, which feeds a component video signal to the HDTV. (Newer HDTV sets can accept DVI, which is delivered by lots of newer video cards, and even HDMI, which, if it isn't available as an output from a PC yet, probably will be soon.)

 

Keep in mind that the maximum resolution of even the best PC displays (and video cards) falls far short of the resolution of run-of-the-mill dSLRs now. But good images still look great on them, as they do on the HD sets.

[scott_eaton]

<I>If so, I'm going to stay with my 35mm slide project a lot longer than I thought.</i><P>I've been throwing more than a few flaming snowballs into this debate for awhile, and will be happy to throw some more. I used to use a MF projector for lab work when we had to show film proofs to fussy clients. We used fixed matte screens, color corrected projection bulbs, and very carefull alignment to insure the best quality presentation so we had little chance of missing details which would produce costly re-shoots.<P>After having that experience, I'm really not impressed looking at 35mm slides projected on some warped lenticular/glass bead K-mart projection screen with a 60watt tungsten appliance bulb regardless of what kind of lens you have. <P>The digital route may not afford the 'potential' resolution of your film, but if that's really your concern, I don't know why you are messing with 35mm toy format anyways, so you kind of defeat your own point. With digital projection of any sort, via from scanned film or hooking your dSLR to a Hi-Def, I'm assured of near perfect color correction, perfect geometry, super high color /contrast ratios, and superb convenience. My only complaints are that there aren't any DVD specs out there yet capable of taking full advantage of Hi-Def, which means you really need a PC with a digital out option to use the full vertical rez of hi-def. Even so, my 10D hooked to my 65" Pioneer looks absolutley spectacular.

[samuel_dilworth]

With respect to Christof for his useful post, computer magazines are possibly the last resource I would turn to for advice on anything audio visual. While the people who write for them are sometimes entertaining and occasionally even computer-literate, they suffer from an ailment common to most magazine hacks: embarrassingly poor taste coupled with an almost total inability to discern quality. If they suggest 1.8 metres as a suitable distance to view a 1.2 metre XGA image one can safely assume they are talking about half-blind computer addicts like themselves: and indeed, anyone who looks at their computer screen from the appropriate distance (i.e. around 18 inches for a typical notebook screen) will note with little surprise that pixels are a problem.

 

Higher resolution displays and projectors are available, but analogue slide projectors remain in an entirely different class for viewing photographs. For someone who associates slide projection with their uncle's ancient Kodak Carousel and keystoned images on the living room wallpaper, I'm sure a good digital display looks pretty nice. (Thankfully, it is more difficult for the clueless to screw up an image on a bright rectangular display than with a slide projector.) I've seen some good displays in appropriate environments and I must admit I have been surprised by how good they can look, but that is because I had very low expectations rather than because they come close to analogue projection: they don't. Also, HDTVs are limited to small sizes (although digital projectors don't suffer from this problem). For my own slide projection I use a Leica P 600 with the five-element Leica Super-Colorplan lens, and in a dark room, with dark walls, at a display size of 10 x 15 ft, I can assure you the quality is something to behold. Think cinema, but much better quality. Of course this solution also costs a lot less than a plasma screen HDTV, unless you're one of those weird types who insists on having a "home cinema" anyway.

 

I do sympathise with those trying to keep thousands of slides physically organised though.

[samuel_dilworth]

Naturally, anything shot on 35 mm is worthless to Scott Eaton.<p>

 

<em>With digital projection of any sort</em> [...] <em>I'm assured of near perfect color correction</em><p>

 

With slide projection, colour is also perfect. One's eyes adjust to the "white" provided by the bulb.<p>

 

<em>perfect geometry</em><p>

 

Like I said, the clueless can't mess up digital. Thankfully some of us can get an optical axis perpendicular to a screen.<p>

 

<em>super high color /contrast ratios</em><p>

 

But not as high as slide projection, of course.<p>

 

<em>and superb convenience.</em><p>

 

True.

[john_pavlakis]

Projection accelerates slide fading, FYI.

[samuel_dilworth]

And smoking causes cancer, eating oysters increases dioxin levels in the liver, religion causes war, reading Joyce causes depression. Almost anything enjoyable or stimulating has bad side effects. To quote the founder of Dignitas, "life is an illness spread by sexual contact".

 

I have a rather more optimistic view, and find the satisfaction I get from projecting slides worth the imperceptible damage to the slides.

[GerrySiegel]

I have been wondering about this display thing for a while now. Digital cameras have an NTSC/PAL output,ancient stuff. And the Sandisk Photo Album player I am looking at buying seems to be rigged for the NTSC or PAL specification. What one will need-guessing here-and I don't see being locked to a computer video card- is a way to go from a CF camera card or other hard disk (where one can organize,sort and play with images) to the DVI input of the new displays.<p> Excuse me if I don't savvy the tech terms,but you get the idea. The beauty of TV and monitors is the backlighting which is more like the transparency backlit.<p> And here I side with you,Scott. You see the future of viewing IMO. It is great to watch off the telly..wall size soon!.<p> Slide shows will always have the set- up humbug (I used to do it laddies) and the washout effect of dark room with the lamp on in the corner so the dog doesnt trip on the cord:-).<p> I wonder what is coming out of the laboratory to deal with Photo Color's question..

[photo_color]

I would like to thank everyone for their very thought provoking answers.

 

I did not think about the fact that one person mentioned that current DVDs are non-HD and therefore won't display the pics in HD. I guess that will change with the introduction of HD DVDs in 2006. But, even then, it appears from the answers so far, that although the results will look very good, the full resolution (4mp and above - 2272x1704 and more) of the pics won't be shown. While it's true that if you sit far enough away from a screen, then pixels won't show, but also, sitting even further, not all the available resolution will show,although it may not matter that much, depending on the situation. I guess it's something I'll just have to actually try out someday.

 

I have seen a demo of the Sony's Blu-Ray, on a digital prototype medium for the movie Lawrence of Arabia. The demo compared it to the regular DVD, using a very expensive digital projector in a darkened room on a large screen. Very impressive - the new technology blows away the regular DVD by far,that it doesn't seem like the same movie. So, HD DVDs for motion pictures, and perhaps even to a greater extent for still picture display should be great!

 

I have used medium format projectors (6x7 - both the Mamiya Cabin and an expensive German model), and yes, the results are far superior to 35mm. But, it requires far more work to mount the glass slides, and show them essentially one by one. So for me, the trouble was not worth staying with medium format (But, now I also use 8x10, in addition to 35mm, but that's another story )

 

The basic question I'm dealing with is that, it appears that even what some call the 'toy 35mm film' format would give superior results in projection (using a high quality projector/lens - like Leitz, or a Kodak with a really good lens, properly aligned to a matte white screen, not the run of the mill Kodak with poor lens and carelessly used with a poor screen) to that of any foreseeable (in the next 15 years) projection of digital pictures. So, if 35mm is a toy, then digital of less quality than a 11mp DSLR is what ? :-)However, maybe the digital presentation would provide very pleasing pictures, esp. if done on bright HD medium that doesn't need a darkened room, etc. Convenience I guess will always win out in the end as long as the quality is decent.

 

I've always preferred viewing slides to viewing prints, although I like prints too. I just don't want to give up the viewing of slides or a reasonable substitute. Most people prefer prints, and don't seem to care about such things as viewing the image in another medium such as projection, and virtually all of the information about imaging (magazines, etc.) seems to be related to producing prints. So, therefore, again, I do appreciate everyone's responses!!

[glen_nicholson]

What's the best way to get the pics on an HDTV?

 

My DVD player doesn't like anything but low-res JPEG files.

 

And then I can only display pictures in the sequence determined by the CD/DVD disk.

 

I was wondering about one of those new video recorders with built in hard drives; perhaps I can load images from the DVD to the hard drive, then sort them for slide shows.

 

Or is it best to use a dedicated PC connected to the TV with appropriate software to sort the slides?