Photoclubalpha

I have put the full resolution version of this shot on pBase, downloadable:


http://www.pbase.com/davidkilpatrick/image/104521336
with no black border or size reduction as the previous one. I have printed this tonight at 20 x 16 size and there's no way you could get this quality, short of using 6 x 9cm rollfilm, in the darkroom. I wish I could show you the print, but if you download the image, and have an Epson 3880 or similar large printer, try it.

Also, a driftwood shot - what superb driftwood - this is the kind of wood I would harvest if I was making musical instruments or carving ornaments!


http://www.pbase.com/davidkilpatrick/image/104521554
Also downloadable at full resolution. f/16 at 50mm on the 28-75mm.

Here are some thoughts - the 17-35 and 28-75mm need stopping down for best results. The A900 needs stopping down to get adequate depth of field for many shots. So, owning a 24-70mm CZ which is more useful wide open is not so valuable; at apertures like f4 or f8, or even f11, there is often just not enough depth of field. But - if you want fantastic differential focus effects, nothing works better than primes like the 50mm f1.4 or 100mm macro f2.8 (or indeed, 80-200mm f2.8 and 70-200mm f2.. So, I am not missing the 24-70mm.

Warning - the A900 is not necessarily a step up from the A700. To get the same depth of field at the same angle of view (i.e. 28mm instead of 17mm etc) you need 1.5 stops smaller aperture. That means using ISO 200-400 instead of 100, or ISO 400-800 instead of 200. And, it means that you need to change your habits. Program setting works fine on the A700, usually there is enough depth of field. On the A900, Program generally uses too wide an aperture. So does flash, where you have no choice over aperture unless you boost the ISO. I love the A900 but I am not blind to the reasons why it is NOT the right solution for everyday shooting!

David

David Kilpatrick wrote: Warning - the A900 is not necessarily a step up from the A700. To get the same depth of field at the same angle of view (i.e. 28mm instead of 17mm etc) you need 1.5 stops smaller aperture. That means using ISO 200-400 instead of 100, or ISO 400-800 instead of 200. And, it means that you need to change your habits. Program setting works fine on the A700, usually there is enough depth of field. On the A900, Program generally uses too wide an aperture. So does flash, where you have no choice over aperture unless you boost the ISO. I love the A900 but I am not blind to the reasons why it is NOT the right solution for everyday shooting!

David

It's there any difference between the A900 and 35 mm film, regarding DOF?
or it's just that we have to re-learn/understand how to photograph with the A900, after some years in the APS-C world they forced us to live?

Regards

David Kilpatrick wrote:Here are some thoughts - the 17-35 and 28-75mm need stopping down for best results. The A900 needs stopping down to get adequate depth of field for many shots. So, owning a 24-70mm CZ which is more useful wide open is not so valuable; at apertures like f4 or f8, or even f11, there is often just not enough depth of field. But - if you want fantastic differential focus effects, nothing works better than primes like the 50mm f1.4 or 100mm macro f2.8 (or indeed, 80-200mm f2.8 and 70-200mm f2.. So, I am not missing the 24-70mm.

Warning - the A900 is not necessarily a step up from the A700. To get the same depth of field at the same angle of view (i.e. 28mm instead of 17mm etc) you need 1.5 stops smaller aperture. That means using ISO 200-400 instead of 100, or ISO 400-800 instead of 200. And, it means that you need to change your habits. Program setting works fine on the A700, usually there is enough depth of field. On the A900, Program generally uses too wide an aperture. So does flash, where you have no choice over aperture unless you boost the ISO. I love the A900 but I am not blind to the reasons why it is NOT the right solution for everyday shooting!

First off, I really like that first photo. Well done!

The very shallow dof photos are quite good and interesting, but they seem to be an obsession with some people these days. I suppose it is a fad. I have noticed that some people use it because it can often be used as a crutch to make a good photo. Nothing wrong with it, but I am a bit surprised at the extremes some people go to get it. Need that 85mm f1.4, 135mm f1.8, etc. Still too much dof with lenses like that on an A700 so need the bigger sensor in the A900 for a very slight decrease in dof. Very shallow dof is one among many, many techniques that one can use to add interest to a photo. There are some people, especially on another well known forum , who seem to equate the narrowest dof as the be all and end all. David, as you mention here though there is the other side of the coin. You know, with my A700 and even with the lenses I use, which are not super fast, I can often get a fairly shallow dof if I really want it.

I like them, they are both nice. I would prefer the second image without the walking person in the distance though, then the photo would have a stronger feel of isolation that the driftwood suggests very strongly with all those dramaticly-coloured lifeline textures and curves that's enhanced by the light...

Well, it's just me.

Thanks for sharing the info on the lenses and cameras too.
Yildiz

pakodominguez wrote:It's there any difference between the A900 and 35 mm film, regarding DOF?
or it's just that we have to re-learn/understand how to photograph with the A900, after some years in the APS-C world they forced us to live?

We never enlarged 35mm to 100x60cm to view it from 50cm distance! That's what happens when I check my A900 shots on screen at 100%. Yes you do have to learn to set f11-16 when f8 would have been fine on APS-C - simple as that. For an identical print size, the difference is 1.5 stops down needed to get the same depth of field, with the same angle of view of lens. If you want to make very big prints, assume 2-2.5 stops down.

David

aster wrote:I would prefer the second image without the walking person in the distance though, then the photo would have a stronger feel of isolation that the driftwood suggests very strongly with all those dramaticly-coloured lifeline textures and curves that's enhanced by the light...

I have several versions and views of that driftwood tree, including one without the person, a panoramic with the lighthouse, view from other angles etc. I liked the one with the figure. I also have examples at f5.6 and f16 to show different depth of field.

David

David
thank you for sharing.
Fantastic shots

Is there a simple formula calculating DOF..........with parameters including size of film/sensor, focal length, aperture, distance of object from the lens etc

The driving force to go for A900 from A700 with be huge leap in image quality

Mark K wrote:Is there a simple formula calculating DOF..........with parameters including size of film/sensor, focal length, aperture, distance of object from the lens etc

Look here: http://www.dofmaster.com/

Here is a website run by a friend of ours - Shirley did the research for the Grey Card back in the 1990s, testing a wide range of materials, and I designed the folding chinagraph writable white-grey card basing it on a concept by Ian Gee FRPS FBIPP. Douglas West suggested the production method of making a 'book cover' using boards and vinyl, but we were paid by Paterson Photographic to design the product and write the original technical manuals. At some point, Paterson went through one of their usual upheavals and Douglas ended up with the right to market the card. He does credit Icon Publications Ltd with the development work, which is kind of him, as it was 'work for hire' back then and he's not obliged to mention it!

http://www.photo-software.com/

His software packages calculate all sorts of stuff which can be useful.

David

Henry, I couldn't agree more, I get the impression that what some are comparing is, background smudges, the actual subject is of secondary importance, it seems, as unbelievable as that sounds...go figure.
Greg
ps The A900 should be great for background smudges, it could even be a "must have" camera for smudges.

I liked that rocky shore photo when you first posted it David, it would look awsome printed out in very large size and framed.
Greg
ps Alas, I only have A4 printers myself.

I guess I should get some of that Adox CMS 20 Film, as it's meant to be the last word in ultra fine super big print sizes. Been meaning to try it for a while now..

David's shot is pretty impressive though, have to say, def not lacking in details!

EFKE KB14 - aka Adox ISO 20 film - used to use this back in the 1970s and early 80s. It was always best developed in Neofin Blue but responded well to two-bath treatment as well, especially Tetenal Emofin. Acufine's Diafine developer was too caustic in the second bath and produced about ISO 50 highlight densities with strikingly empty shadows!

I did acquire some Adox powder-formula developer at the time as well, but it was very difficult to dissolve and needed filtering before use. Ilford's remarkable glycin-based one-shot powder formula, Hyfin, was also very good with KB14 but nothing like is now made (the chemicals are about as friendly as asbestos).

David

I think you have got a better 28-75mm D than me ... everything i have tried this weekend on my lens is sharp in the middle, and even on some left end ... but on the right all things looks blur ... .

Here is some examples here :
28mm F/9.0

http://www.pbase.com/nadeauf/image/1045 ... iginal.jpg

http://www.pbase.com/nadeauf/image/1045 ... iginal.jpg

I don't know if it is somethings wrong with my technical adjustment ... but i starting to thinking i will have to leave this lens .

Regards,

Frank

InTheSky wrote:I think you have got a better 28-75mm D than me ... everything i have tried this weekend on my lens is sharp in the middle, and even on some left end ... but on the right all things looks blur ... .

Try setting the AF Micro Focus Adjustment to -5 and -10 and make test shots with these settings. It is very rare for a lens to be perfectly parallel to the sensor plane, and I think what is happening here is that the right hand side is focused beyond infinity when the centre is on infinity (or distant subject), and the left hand side is actually focusing a bit close.

But it could also be a poor lens.

I noticed that with the A900 test camera I used, the right hand side of all the pictures was not as sharp as the left, at the press conference. This can be due to a slight error in the camera body, in which case, you should ask to try another A900 if that is possible. To test it, use the shortest focal length at a wide aperture, that you can. These problems are common enough in Canon 1Ds models so it would not be surprising to see it happen in an A900 - though so far, they seem better made.

David