tonybrown

Here's an example of how this in practice affects my work. The Canon 1Ds mk III has 14 bits of resolution as oppopsed to the usual 12 bits. The extra 2 bits are used in the highlight range so that wedding photographers can extract fine detail from wedding dresses etc. Under normal photography these 2 bits are under-utilised. So in photographing a rose, I deliberately overexposed by 2 stops, giving me extra dynamic range. (There are some articles on this). Importing into camera Raw indicates the rose is grossly overexposed, but adjusting exposure in Raw brings the highlights into visible range and at the same time pushes the noise down two stops. In order to preserve some of the detail in the low lights I need to reduce the contrast - a linear contrast becomes my target. So I set the contrast to zero on the basic slider and to linear on the tone curve preset. And I end up with a beautiful rose with some really nice delicate lighting of the petals. Clearly I don't think that high contrast is advantageous in this case. http://www.photo.net/photo/7539538

Colin, I appreciate your explanation. It does line up with some of the articles on the Adobe web site. The fact is though, the 'Tone Curve' does have a preset (forget the curves) which permits adjustment to linear, medium, strong and custom contrasts and these modify the contrast that you set with the contrast slider in the basic mode. Probably no contest there? So what combination of the two contrast controls is equivalent to the native contrast of the physical optical sensor? Is it zero on the basic slider and linear on the tone curve preset?

 

Further, Adobe suggest that the tone curve is a fine adjustment tool. That would be ok, but the tone curve preset works all the way from linear to strong contrast. In that way it competes with the basic slider adjustment. I've worked with this for a while, and it still puzzles me. In practice I do have two methods of strongly controlling the contrast and they are not independent.

 

Granted that you can use the basic slider control to get the contrast that "looks" right to you and as you said - simple, easy, bang boom done. But I would really like to know how to get the native contrast set by my camera before making adjustments. This has implications for noise etc.

 

Tony

There's an oddity in Camera Raw: Under "Basic" you can adjust Contrast, for example to zero. Under "Tone Curve",

select Point, and you can preselect Linear, Medium, Strong and Custom Contrast. Both the Basic and Tone Curve

controls operate independently, simultaneously. So for example under Tone Curve you can select 'Linear" and under

Basic you can adjust for High Contrast, setting the contrast control to 100. What you get is the combination, neither

linear nor high contrast. So if I want to go really linear (using all 14 bits available in Canon's 1Ds mk III) I set Basic

Contrast to zero and Tone Curve to linear.

Surprise: its the same in Lightroom 2.

So, wouldn't it make sense to give the Basic and Tone Curve controls exclusive control of contrast - either one or the

other? Am I missing something here?

This thread must be a record. Interesting, though. A couple of thoughts - 1) in digital it is very difficult to accurately reproduce a deep red colour - but not impossible. I spent time this summer capturing and printing a deep red rose. The printing part was the most difficult and following my usual process gave me rather purple reds. However, reducing the luminance of the reds and oranges while increasing the saturation gave me the desired result. My camera a 1DsmkIII and printer i9900. In my view the primary problem is that a simple 3 colour RGB representation (Adobe RGB) cannot represent everything the camera tries to capture (or what my eye sees) - and incidently this also applies to images scanned from film and represented by the RGB format. 2) The role of the photographer is more important than the camera or the medium. Digital has enabled me to rapidly grow on the photographer's learning curve largely because I have more control over the process and experimentation does not cost me a bean. With over 50 custom functions on a 1DsmkIII there's lots of room to go wrong - but also lots of room to combine serious science with art ... and I'm a scientist. Regards to all ... it was an interesting read.

One year later, but I'd like to add this thought. First of all, thank's to Kim for raising this subject, there have been some truly insightful answers - even the one's I didn't like!

 

They say that beauty is in the eye of the beholder. I see the art of Robert Bateman as truly great art. He is also a highly motivated nature conservationist. His art appeals to those who share a kindred spirit. Others deplore his use of art to promote conservation. They feel his art lost something due to commercialisation. So we tend to have filters through which we see 'art'. Perhaps a good illustration of this is the number of forums we have on photonet. The same photograph can receive vastly different critiques in two different catagories.

 

In the end, a photograph that appeals on a number of levels, that clearly portays something I value in our multidimentional world and evokes in me some sense of emotion, enlightenment, and even thankfulness, or perhaps pity, compassion, comfort ... that is a photograph that I would describe as great. Again, that's in the eye of this beholder.

A lot has been said about the 400mm f5.6 L prime being sharper than the 100/400mm zoom - and it is sharper. However the zoom is still a very good lens and has enough resolving power that with my 12 megapixel EOS 5D it is not really an issue. What gives the zoom the edge for bird photography is the image stabilization which is superb. Having said that there seems to be (in Europe) a new version of the prime with IS ..?

I agree with what has already been said: a new 600mm f/4 should not have this much CA. I downloaded your JPEG of the bald eagle and tried correcting the CA in Photoshop CS3. It was easy to correct the CA of the yellow in the top right quadrant, but not the blue in the bottom left quadrant and it was correctable in the bottom right quadrant but with different numerical values. This suggests to me that something is really wrong with this lens. I have never seen anything like it with my 100/400mm zoom.

I can empathise with most of what has been said on this post. Many photographs with a mean rating of about 5 are still receiving 3's which by the laws of statistics could be discarded as a rogue rating. Given that photo.net is computer based, how about a rating of the raters and a booby prize for the most frequent low rater?

Jan: there are arguments both ways on this choice. There is no doubt that dealerships make a lot of money on extended warranties. Nevertheless I always buy the extended warranty. This has paid off big time for me. A few years ago I upgraded my Canon 10D for a 20D and the dealership allowed me to transfer the extended warranty also. A year later the Canon warranty had run out. Meanwhile I had discovered a feature (auto power down) of my 20D was not working. When I got back to town, the warranty had run out, but the extended warranty covered the problem. Canon attempted to repair the 20D and at their option decided to give me a new camera! Last year I added a 5D to my collection and, of course, I bought the extended warranty. For me its an insurance against 'infant mortality' - the sort of failure that occurs in the first year or two of a product. Hope this helps, Tony.

Chip: I have owned a 10D and now own a 20D and 5D. The 10D is a great camera. I was disappointed with the lighter 20D body, and the pixel size is smaller. It may be my imagination, but I think my colours were better on the 10D than the 20D (taking fall photos). They were certainly better on the 5D than the 20D - apparently due to the larger pixels. On the other hand I've had some great telephoto shots with the 20D with its smaller pixels. I am not impressed with the 20D flash and the 5D does not have one. The 30D is a small improvement on the 20D, better shutter - they say. All in all, the 30D is a better camera than the 10D, I think it is worth the upgrade.

A good example of the lower density of Rag Photo paper is the Ilford Fine Art with a weight of 190 gsm and a calliper of 15.7 mil. The conversion table would make this about 8.1 mil. Quite a difference.

Thanks Dan. I do have a conversion table, but I didn't trust it because the rag paper has a different density to regular paper. Rag papers are generally much less dense, hence thicker. Hence my problem.

Does anyone know the thickness (calliper) of the Hahnemuhle photo rag paper

with 188 gsm? I cannot seem to find it anywhere. Thanks, Tony

Moray: I also have a Dell laptop (Inspiron 5150) and have concluded that there is no real merit in trying to calibrate the LCD monitor. My object is to produce faithful prints, so I shoot Adobe RGB (RAW) with a Canon EOS5D, print with a Canon i9900 using Photo Paper Pro and Canon profile PR2. By using my EOS5D as a Colorimeter and viewing the results in Photoshop CS2 Bridge I can confirm that my colours are accurately printed. The EOS5D makes an excellent colorimeter and comes for free. - Tony

I also have an i9900 and found the blue/green tint when printing neutral grey, particularly in the mid/dark grays - just like your illustration. I found this to be paper dependent. The Canon Photo Paper Pro PR101 has the flattest colour spectrum and showed very little colouration with neutral gray over the entire intensity scale. The Canon Matte paper MP101 has a blue bias particularly in the mid-dark grey region. Incidently, so does Henry's satin paper. The EPSON Enhanced Matte paper was much better with a much more neutral grey spectrum over the entire intensity range. Incidently I used my EOS 5D and my EOS 20D cameras as colorimeters to measure the colour of my prints with a light temperature of 5500K (flash). Adobe Photoshop CS was used to measure the image colour balance for each test. Hope this helps. Tony

I recently learnt from Canon USA that the print head gap on the i9900 printer

is adjusted automatically to the paper calliper if the paper is a Canon paper

and you use the right profile. I also learnt that they do not offer a profile

for their fine art paper for the i9900 and prefer you to buy their pro9000

printer for this use. They also said I can use other papers such as the Ilford

papers provided I specify the Canon profile that corresponds to the Ilford

paper calliper. So I checked the calliper of various papers and this is what I

found:

Canon Photo Paper Pro PR101, calliper 9.1 mil, works with Canon profiles PR1

and PR2.

Canon Matte Photo Paper MP101, calliper 8.5 mil, works with Canon profile MP1.

Canon Photo Paper Plus Glossy PP101, calliper 10.5 mil, works with Canon

profile SP1.

Canon Fine Art Premium Matte FAPM1, calliper 11.6 mil, no Canon profile

available.

Canon Fine Art Photo Rag paper FAPR1, calliper 12.2 mil, no Canon profile

available.

According to Canon, FAPR1 and FAPM1 are too thick for the i9900 transport i.e.

it was not built for thick paper and stress or damage could occur.

Meanwhile Ilford recommend their Galerie Smooth Fine Art (rag) paper at 15.7

mil calliper for the i9900 and they publish a profile for it. Also Ilford

Galerie Classic Pearl has a calliper of 9.8 mil and the Ilford Galerie Smooth

Gloss has a calliper of 10.8 mil. The latter two papers could be used with the

Canon SP1 profile for reasonable head height (my guess). Interestingly Ilford

offers exactly the same profile for these papers: so there is no adjustment of

head height. Does anyone have some words of wisdom on the use of non-Canon

papers with the i9900? Printer longevity etc.?