yuri_wolf

Dry habitat<div></div>

I use Power-2000 - it doesn't live up to the "1 hour" claim, but still works for me faster than Nikon's original charger. 12-Volt adapter is a bonus - the combo goes with me to all long trips.

<I>Is there a point to using DX glass on FF sensors if you can only use like 10% of the zoom range? Please, if there is a point other than "but you CAN!111" then please enligten me.</I><BR><BR>

 

Two words - <B>emergency backup</B>. 12-24 DX gives you 50% of the range, BTW (sorry, I know you haven't asked).

Take a piece of white polyester cloth - pocketable, understructible in normal field conditions, washable and multi-purpose in an emergency. Calibrate it at home against a real gray card and don't forget to apply the correction factor in the field. Also great to set white balance with digital.

I. Prepare color template (once per color):

 

1. Pick a color you like (preferably from the midtones range). You can lift it from any source image you have.

 

2. Make a small empty new image (e.g. 100x100 pixels).

 

3. Use bucket tool to fill this image with your selected color.

 

4. Convert the image to LAB and save the file for future use.

 

II. Toning a photo (once per image).

 

1. Convert your photo to monochrome using your favorite method (e.g. with channel mixer/monochrome).

 

2. Open your saved color template and resize it to the size of your photo (e.g. 100x100 -> 3008x2000).

 

3. Select-all your monochrome photo, copy it and paste it into the L channel of the resized color template.

 

4. Convert the result to RGB and save the toned image.

 

The idea is to rely on LAB colorspace to separate luminosity and color information, and use luminosity data from your photo and color data from your template.<div></div>

<B>Dan:</B><BR><BR>

 

<I>Yuri, you're confusing long focus lenses... with telephoto lenses.</I><BR><BR>

 

I can easily be - I am not an optical engineer. :-) So you are saying that "telephoto" is a specific design (converging group in the front and diverging at the rear) and "long focus" lens is a generic name for the "longer than normal" focal length lens. Do I understand you correcly? Then there can be, at least in principle, "normal telephoto" lens or maybe even "wide angle telephoto" lens, right?<BR><BR>

 

<I>The effect of this design is to make the lens' back focus is usefully shorter than its focal length.</I><BR><BR>

 

...effectively pushing the rear nodal plane inside the lens barrel, right?<BR><BR>

 

<I>I have a 12"/4 Taylor Hobson telephoto whose back focus is ~ 85 mm. That's back of rear element to film with the lens focused at infinity. And I have a 30 cm/9... Cooke Apotal whose back focus is ~ 300 mm.</I><BR><BR>

 

Are they designed for the same camera format?<BR><BR>

 

<I>Absolutely positively not a telephoto lens. Positively absolutely a long focus lens</I><BR><BR>

 

I think I've got it. What about wide angle, then?<BR><BR>

 

<B>Paul:</B><BR><BR>

 

<I>The "magical" correlation between the calculated diagonal method for "normal" and the visual "myth" of no magnification seems to work. Perhaps it's just a coincidental observation?</I><BR><BR>

 

No, I guess it isn't a coincidence. I'd guess if you are reading this on a desktop or a laptop computer (not a hand-held device), distance between your eyes and the screen is about equal the diagonal of the monitor - most likely not twice longer or twice shorter. The <I>"typical"</I> behavior of a <I>"normal"</I> human eye in <I>"normal"</I> conditions roughly corresponds to a 40-60<SUP>o</SUP> "cone of attention" which covers the "distance=diagonal" case. The myth is that the "normal" lens is <I>defined</I> this way.<BR><BR>

 

<I>As for the magnification of cameras viewfinders being different...NO, they are virtually the same.</I><BR><BR>

 

I haven't researched this thorougly, but I believe I see the difference in the viewfinder magnification between, say, Nikon F100 and F65 - with the same lens. Again, I refer to you to the earlier quoted thread - people clearly state that there is a difference.<BR><BR>

 

<I>It also makes a Pentax 50mm, a Nikon 50mm just as a Leica 50mm all the same 50mm.</I><BR><BR>

 

I would disagree - what really makes them "the same 50 mm", is that they produce the same size of image with the same imaging format - regardless of viefinder magnification (with Leica being a rangefinder, viefinder can be really anything at all).<BR><BR>

 

<I>I'm sure there is a city slicker scientist that can answer it more accurately with all sorts of equations and none the less wrong. But as the farmer's son, I say it'll rain 'cause the leaves are white side up. Does that make me wrong while we discuss all the reasons under the same umbrella?</I><BR><BR>

 

Yeah, right. Next time these scientists will tell you that umbrellas don't cause road accidents, despite the perfect observed correlation between the number of umbrellas on the street and the number of insurance claims. :-)

<I>But for some magical reason it seems to apply in almost all cameras.</I><BR><BR>

 

I guess I need to make an additional remark on the "magic" part. I don't fully understand myself the engineering part involved (I hope somebody versed in real-life optics will chime in), but from the optical design point of view there are three classes of lenses: "wide", "normal" and "tele". "Normals" are those whose focal length is close to the diameter of the image circle (those magical 53 degrees of the angle of view, give or take some); "teles" are, by definition, significantly longer than that; "wides" are shorter. They are designed differently. Incidentally, this is why you can make a decent 10x zoom going from, say, 50 to 500 mm (normal to tele) but 18-180 (wide to tele) would be a disaster on 35 mm cameras - in the first case you compromise between two sets of requirements, the second will require to reconcile three of them.<BR><BR>

 

Will somebody expand on that?

<I>But for some magical reason it seems to apply in almost all cameras. WHY?</I><BR><BR>

 

Says who? :-) Different people see very differently and differnt cameras have different viewfinder magnifications.<BR><BR>

 

See for example <A HREF="http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=006Voy">this thread</A>; specifically posts by Axel Farr (Nov 18, 2003; 06:29 a.m.) and Oliver S. (Nov 18, 2003; 10:10 a.m.).<BR><BR>

 

But there is no magic - a cone of 40-60<SUP>o</SUP> <I>usually</I> is our everyday "tunnel of vision" - so it works after all when you view the print.

<B>a)</B> and <B>b)</B> are mathematically equivalent:<BR><BR>

 

Phi_diag = 2*arctan(1/2) = 53<SUP>o</SUP> if diagonal is equal to the focal length<BR><BR>

 

It just happened to be traditionally defined as <B>b)</B>.<BR><BR>

 

<B>c)</B> is an urban myth. First of all, the "same magnification as the human eye" involves the viewfinder magification, that can differ on different cameras with the same lens. Second, the magnification of a human eye is variable.

Also depends on the kind of physical activity you are accustomed to / willing to have. If you restrict yourself to 100 yards from the nearest parking lot, Tetons indeed could be covered in 2-3 days - there are only so many overlooks on the park roads. If you plan to go for even semi-serious hiking, a month might not be enough to explore.<BR><BR>

 

Tips (in addition to already given early morning/late evening advice): I would venture to say that sunset at the Oxbow Bend and early morning light on Mt. Moran from the String Lake trail is the Teton equivalent of "me and the Eiffel Tower" shot in Paris - done millions of times but shouldn't be missed anyway. :-)

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<I>...increase image resolution by interpolating pixels that do not exist in the original image and so, increase pixel count. It creates false 'detail'...</I><BR><BR>

 

"Pixel count" - yes. "False detail" - yes. True resolution - I wouldn't say so. You can't re-create the information that hasn't been captured originally - only fake it (thus the reference to Shannon in my first post in this thread).<BR><BR>

 

All of this would have been usless pedantic nitpicking but let's return to the start of the discussion. Upsampling the digital capture to the pixel count of the scan <B>is</B> a reasonably fair comparison, if only slightly loaded against digital<SUP>*</SUP>. You do not "artifically boost resolution" this way, which is simply impossible, you are adjusting the precieved image size to make visual comparison easier.<BR><BR>

 

*- Why? Because you when you upsample the smaller image you magnify all the imperfection and artifacts that existed there, comparing them with "original" capture - the scan in NL's case. If you downsample the larger image to the size of the smaller one, you potentially throw away the details that were there, so if you want to load your test in favour of digital capture versus a high-res film scan, this is the way to go. :-)

Meryl Arbing: <I>You artificially enhanced the digital image by using editing tools to boost resolution.</I><BR><BR>

 

Please, share the knowlege - what editing tools can be used to boost <B>resolution</B> (as opposed to sharpness, contrast, number of pixels etc.)? I would love to see that old codger Claude Shannon finally proven wrong! :-)

<I>Is "expose to the right" on a digital camera any different from "expose for texture in highlight" on a film (slide) camera?</I><BR><BR>

 

My understanding is that it <B>is</B> different. Film doesn't quantize the exposure levels differently along the response curve; digital does.<BR><BR>

 

<I>The second image (mid day white clouds in blue sky) on A Practical Guide to Histograms... has lots of highlight... Exposing more to the right than this exposure will clip the highlight and lose the texture in the clouds.</I><BR><BR>

 

Quoting the <A HREF="http://www.luminous-landscape.com/tutorials/expose-right.shtml">Michael Reichmann's article</A>, <I>"The simple lesson to be learned from this is to bias your exposures so that the histogram is snugged up to the right, but not to the point that the highlights are blown"</I>. The idea is to preserve as much info at the time of the capture and <B>then</B> decide how best to deal with it.<BR><BR>

 

<I>The dominance of the highlight ought to allow you to collect plenty of "useful bits". But the highlight is not necessarily the most important element in this image, so what's the good of all the "useful bits"?</I><BR><BR>

 

If you manage to shift the histogram <B>without</B> clipping, you will also move to the right the pixels representing the subject, placing them to the more data-rich zone. Which might prove to be useful if you decide to pull more details from, say, darker trees in the image you've mentioned.<BR><BR>

<I>Some people think that a histogram that is concentrated towards the right end... is generlly better. I understand the theory behind this... but one can also argue that a histogram that desn't conform to this may be a better direct representation of your subject matter and the lighting.</I><BR><BR>

 

Ellis, as I understand it, the <A HREF="http://www.luminous-landscape.com/tutorials/expose-right.shtml">"expose to the right"</A> theory applies to the unprocessed image off the camera - you try to collect as many useful bits of info as possible. The final image, of course, needs to be adjusted to the desired "representation of your subject matter and the lighting".

The non-tourist Utah<div></div>

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Catalina Mountains, AZ<div></div>

I use a D70 for a year, almost exclusively outdoors. Last summer I slipped and fell on some rocks in Adirondacks with the camera in an unpadded shoulder bag. Top LCD cracked and lost function; camera continued to take pictures without problems (although I had to use menus and/or viewfinder display to change settings for the rest of the trip). Nikon Sevice repaired it (of course, they didn't considered it a warranty repair). Still works.

 

So, the short answer is "yes".

Oh, and I messed up the Sugarloaf Mountain link - supposed to be <A HREF="http://www.yurikira.com/bin/getThree.cgi?List=Needwood&Mode=select&Dirn=&Picn=04h01n1955">this</A>.<BR><BR>

 

Sorry for the extended bout of self-promotion. :-)

Oh, and the <A HREF="http://www.yurikira.com/bin/getThree.cgi?List=Potomac&Mode=select&Dirn=&Picn=01S7914">Great Falls National Park</A> (30 min driving).

Too much to list, especially not knowing what do you shoot.<BR><BR>

 

As for the outdoor stuff, among the places that hasn't been mentioned yet, you have <A HREF="http://www.yurikira.com/bin/getThree.cgi?List=Needwood&Mode=select&Dirn=&Picn=04j23n3294">Rock Creek Park</A> (15 min driving); <A HREF="http://www.yurikira.com/bin/getThree.cgi?List=Needwood&Mode=select&Dirn=&Picn=02k0404">Black Hill Regional Park</A> (20 min driving); <A HREF="http://www.yurikira.com/bin/getThree.cgi?List=Wheaton&Mode=select&Dirn=&Picn=01F0408">Brookside Botanical Gardens</A> (30 min driving); <A HREF="http://www.yurikira.com/bin/getList.cgi?List=Needwood&Mode=select">Sugarloaf Mountain</A> (30 min driving); <A HREF="http://www.yurikira.com/bin/getThree.cgi?List=Catoctin&Mode=select&Dirn=&Picn=04e30n0003">Catoctin Mountain National Park</A> and <A HREF="http://www.yurikira.com/bin/getThree.cgi?List=Catoctin&Mode=select&Dirn=&Picn=04f06n0002">Cunningham Falls State Park</A> (1 hr driving) and way more beyond 1 hr driving distance.<BR><BR>

 

P.S. I linked it to pictures on my site, but Google should be able to point you to the descriptions/directions.

Sandstone/conglomerate sculpted by erosion.<div></div>

<I>Now, the road is not a 4 wheel drive road, but it is extremely - and I can't emphasize that word enough_ ROUGH</I><BR><BR>

 

I have to concur. It <B>is</B> passable even in a low-clearance compact car (I did that the last December), but you need to know what are you doing and go <B>real slow</B>. Busting a tire out there would be, to put it mildly, quite unpleasant. It took me 90 brain-scrambling minutes (washboard is an understatement - jackhammer, maybe) to cover 27 miles, so unless you are sure about the quality of your tires, be prepared to go way slower than 30 mph.<BR><BR>

 

Have fun - it's a great place.

I use Sigma 105 f/2.8 EX for five years; have nothing to complain about. Take it into the field regularily.<div></div>