Ian Stuart Forsyth

Ian Stuart Forsyth

Lives in Canada Canada
Joined on Oct 16, 2010

Comments

Total: 15, showing: 1 – 15
On Readers' Showcase: Nature and Wildlife article (28 comments in total)

This has moved this site in a positive direction
Thank you

Direct link | Posted on Aug 4, 2014 at 05:01 UTC as 11th comment
On What is equivalence and why should I care? article (2004 comments in total)
In reply to:

dtmateojr: Very basic question:

Can this "equivalence" ever be achieved with film? Consider Kodak Ektar 100 in 35mm and 120 formats. If yes, then how?

If it can't be achieved then either:
1. film is exempted from basic photography
or
2. equivalence-fu is wrong.

This can be easily proven
If I was to use porta 160nc 135mm film and used F2.8 1/100sec for the desired image. I then moved over to 6x6 negative and used porta 400nc and used F4.5 1/100sec they would be taken at almost the same equivalence and thus they should show the same print grain.
If we look at the Kodak site you will see that a 4x6 print from a portra 135 160nc has print grain of 30 and a 4x6 print for portra 120/220 400nc has almost the same print grain at 29
who would have ever thought this was possible
http://www.kodak.com/global/en/professional/support/techPubs/e58/e58.pdf

Direct link | Posted on Aug 1, 2014 at 07:56 UTC
On What is equivalence and why should I care? article (2004 comments in total)
In reply to:

mostlyboringphotog: F-stop is the equivalent aperture. It allows the convenience of same exposure across the FL and the sensor size (4x5, 120, 135, DX, CX, etc). The young guns want to change "equivalent exposure" to mean "total light" and this old timer is saying "not so fast" and for this I get told pejoratively that I am a "denialist" sometimes with the implication that I'm being so "willfully ignorant". As if I'm the only one that is filling up the 150 posts...

Well, this old timer will happily change my mind and that's more than I can say for the "Equivalence". If I change my sensor size more often than the f-stop, then yea, put the "total light" equivalent f-stop on the lens barrel.

Here you go
http://www.dpreview.com/forums/post/54096915
have fun

Direct link | Posted on Jul 27, 2014 at 08:46 UTC
On What is equivalence and why should I care? article (2004 comments in total)
In reply to:

mostlyboringphotog: F-stop is the equivalent aperture. It allows the convenience of same exposure across the FL and the sensor size (4x5, 120, 135, DX, CX, etc). The young guns want to change "equivalent exposure" to mean "total light" and this old timer is saying "not so fast" and for this I get told pejoratively that I am a "denialist" sometimes with the implication that I'm being so "willfully ignorant". As if I'm the only one that is filling up the 150 posts...

Well, this old timer will happily change my mind and that's more than I can say for the "Equivalence". If I change my sensor size more often than the f-stop, then yea, put the "total light" equivalent f-stop on the lens barrel.

@dtmateojr
I would like to third GBs request that you start a thread about this in the Photographic Science and Technology forum.
I have the next 24hr off and need the entertainment

Direct link | Posted on Jul 27, 2014 at 08:22 UTC
On What is equivalence and why should I care? article (2004 comments in total)
In reply to:

lumigraphics: Sorry but you guys botched a bunch of this. :sigh:

"Total light" is completely unimportant. Yes, there is less light hitting a smaller sensor, but it doesn't matter because its a smaller total area. Light PER SENSEL is the same.

And lenses don't matter at all. Given a frame-filling grey card (as an example) a 50mm f/4 and 100mm f/4 will give exactly the same 18% grey image on any sensor size. If lenses didn't work that way, you couldn't have external light meters.

Larger digital formats aren't less noisy because they are larger so they collect more light, its because they can have a lower sensel density. In the film days, it was because you didn't have to enlarge so much with a bigger negative.

smdh...and I'm only on page 2.

"Larger digital formats aren't less noisy because they are larger so they collect more light, its because they can have a lower sensel density. In the film days, it was because you didn't have to enlarge so much with a bigger negative."

And same applies to digital as did in film, the more you have to enlarge the negative ( raw file) the more apparent the noise will become maybe you should read it again

and by the way same density of light falling on a larger format collects more light

Direct link | Posted on Jul 10, 2014 at 04:07 UTC
On z100 photo in Iain G Foulds's photo gallery (1 comment in total)

Nice capture

Direct link | Posted on Oct 12, 2013 at 04:25 UTC as 1st comment
On 013_6777 panolow in the It's up to you!!! #4 challenge (2 comments in total)

Thank you barb

Direct link | Posted on Aug 3, 2013 at 03:10 UTC as 1st comment
On My best picture this week challenge (1 comment in total)

Are pano’s allowed that are composed with several photographs, only using PS to stitching them together? something like this http://www.dpreview.com/galleries/292626105/photos/2585727/gbhifsm-x3-2

Direct link | Posted on Jul 18, 2013 at 01:30 UTC as 1st comment
On dp photo in Ian Stuart Forsyth's photo gallery (2 comments in total)

This was to prove a point that process an image has more to do with the final image than the sensor used. It was shot with a Nikon D800 with custom profiles to mimic the colors of Foveon and final output of a sigma camera

Direct link | Posted on Jun 30, 2013 at 06:33 UTC as 1st comment
On 2590425sdii photo in Ian Stuart Forsyth's photo gallery (2 comments in total)

This was to prove a point that process an image has more to do with the final image than the sensor used. It was shot with a pentax k20d sigma 70-200 F2.8 II ex DG with custom profiles to mimic the colors of Foveon and final output of a sigma camera

Direct link | Posted on Jun 30, 2013 at 06:33 UTC as 1st comment
On 105sd photo in Ian Stuart Forsyth's photo gallery (2 comments in total)

This was to prove a point that process an image has more to do with the final image than the sensor used. It was shot with a pentax k10d sigma 105 2.8 ex with custom profiles to mimic the colors of Foveon and final output of a sigma camera

Direct link | Posted on Jun 30, 2013 at 06:32 UTC as 1st comment

Just what I needed a 560 5.6 with no IS and yes I know Pentax has sr but above 300mm its crap and cannot compete with the others in image stabilisation and by the way wasn’t the Titanic white also?

Direct link | Posted on Sep 11, 2012 at 03:38 UTC as 13th comment
On IMGP3451-2 photo in il_alexk's photo gallery (1 comment in total)

Nice photo congrats on your placing

Direct link | Posted on Aug 4, 2012 at 05:56 UTC as 1st comment
On -42c photo in Ian Stuart Forsyth's photo gallery (2 comments in total)
In reply to:

Poivre: Thank you for these gentle wildlife photos. I like the soft colors and the variety of animals you are able to photograph.

Poivre

Thank you Poivre I somehow missed you Comment

Direct link | Posted on Jan 29, 2012 at 23:45 UTC
On Natures building blocks in the Elementals: Water challenge (2 comments in total)

This was one of my more hardest to capture to date. Used was a sigma 105 marco ,2x conv & extension tubes I tried many different combs most likely was 35mm ext. My biggest obstacle was the dov as you can see its paper thin and any breeze would move the frost. I had also noticed that my body would cause the frost to curl in and out of focus. The photo was manual focused and to fine tune the adjustment I pressed on the base of the tripod leg with my foot and captured the photo with a remote control

Direct link | Posted on Dec 9, 2010 at 03:52 UTC as 1st comment
Total: 15, showing: 1 – 15