RichardT wrote:
Very nice pictures. I was fighting to pick one from 12-24 or a fisheye for my 5D, and now I think I'll take the wide angle first.
I have a fisheye--have had it since D60/30 days. Then I used it and defished it a lot to get wider than my 15-30 (after defished, it came in nearer a 12mm for the 1.6x bodies). I have only used it once on the 5D in almost 2 years and probably should sell it--its 'very fish' on a FF and not a look I aim for most of the time. I find I'm carrying the 12-24 a great deal.
I had considered buying the 24 TS and I'm a fan of TS lenses (love my 45), but decided on the 12-24 and am glad I went that direction instead--at least for now.
DrPablo wrote:
The traditional "proper" (some would say "magic") viewing distance is the focal length multiplied by the enlargement factor. This has been espoused by Ansel Adams for gallery prints, among others. Because of this, the print size doesn't matter because you have to vary your viewing distance linearly with enlargement size.
Yes, thanks...I know and understand this.
To get this viewing distance for a 12mm print...without going through the math...that is half the height of the print (in landscape orientation). Now at 4x6...it's hard to tell the viewer to look at it from 2"...right? Even at 24x36, it is hard to tell the viewers to view at 12". So if the poster print is put in in a 3' wide hallway, at least you have brought the viewer reasonably close...
SoundHound wrote:
For you UWA fans try the Canon 15 F2.8 FE with the ImagetrendsInc.com hemi converter for $30. Nothing like it!
A lot about defish software has been said, what I don't understand is what's wrong with using PShops Lens correction filter...doesn't it do the same?
About sending bad sigma copies in for repair, what has stopped me from buying this lens in the past HAS been reports of spotty QC. So is it really true that 1) the QC is getting better recently?; 2) You can send a new or used lens into Sigma for checkup and repair softness if needed?
I'd be using it on a 1.3X body, so while I could check softness, I couldn't check full frame softness if I wanted to go that route in future, therefore the idea of sending into Sigma for a check either under warranty or "paid for" check if out of warranty is apealing.
Jim Hayes wrote:
A lot about defish software has been said, what I don't understand is what's wrong with using PShops Lens correction filter...doesn't it do the same?
About sending bad sigma copies in for repair, what has stopped me from buying this lens in the past HAS been reports of spotty QC. So is it really true that 1) the QC is getting better recently?; 2) You can send a new or used lens into Sigma for checkup and repair softness if needed?
I'd be using it on a 1.3X body, so while I could check softness, I couldn't check full frame softness if I wanted to go that route in future, therefore the idea of sending into Sigma for a check either under warranty or "paid for" check if out of warranty is apealing....Show more →
Jim, I did use PT Lens for defishing my FE --but are you talking about the one that corrects distortion? I haven't used it in a good long while (not nice with FF defishing). If you are talking about correcting the lens---I think most may use PTLens.
I don't know if the QC has gotten better---but since Spring I have seen no posts with people having gotten bad copies. That suggested to me that it was time to at least try it.
I understand that Sigma will correct it. I didn't have it done but have read posts from others that did. Certainly something to check.
Grant808 wrote:
Yes, thanks...I know and understand this.
To get this viewing distance for a 12mm print...without going through the math...that is half the height of the print (in landscape orientation). Now at 4x6...it's hard to tell the viewer to look at it from 2"...right? Even at 24x36, it is hard to tell the viewers to view at 12". So if the poster print is put in in a 3' wide hallway, at least you have brought the viewer reasonably close...
I guess you're right now that I do the math.
This recommendation becomes unwieldy for wide shots with any format smaller than 8x10. Even with the widest of all 4x5 lenses, which is 47mm, a 4x5 contact print would predict a 47mm viewing distance (under 2 inches).
It's not until you get to 8x10 that this is more reasonable -- I think the widest lens that covers 8x10 is 120mm, so that would give you a 4.7 inch viewing distance from an 8x10 contact print (though this would be identical for a 35mm or APS-C image shot with an equivalent angle of view lens enlarged to the same size). Obviously 2 inches away is too close to focus comfortably, and 4.7 inches is right on the edge of comfort, though this viewing distance would indeed preserve that amazing wide angle perspective. And a 2x enlargement from there would be a big 16x20 print viewed from 9 inches away.
This is one reason why superwide photography just screams for high resolution lenses and capture media, because you're not only enlarging a lot but you're viewing it close up.
Incidentally, very long lenses on 35mm cameras also predict weird viewing distances. A 600mm lens used to shoot a 4x6 print would require a 2.5 meter viewing distance -- i.e. 8 1/2 feet away from a 4x6 print (and 36 feet away from a 16x24 print).
But the difference here is that long tele lenses cause so much compression of perspective that I don't think it's as important to maintain that magical viewing distance -- the experience of seeing details up close with tele lenses supercedes the perspective issue, whereas with wide lenses that perspective issue is more important.
picnic wrote:
Jim, I did use PT Lens for defishing my FE --but are you talking about the one that corrects distortion? I haven't used it in a good long while (not nice with FF defishing). If you are talking about correcting the lens---I think most may use PTLens.
Diane
To be clear, I'm talking about Photoshop CS3 or CS2 lens correction filter-built into photoshop no extra charge. The one under the filter menu... It takes a given image and either pincushions it or barrels it out, straightening the fish curvature. Then you can scale and crop out the corners/edges, tilt the axis of the image if your horizon is off, I think even vignette, etc.
I was wondering with such a tool already built into Photoshop, why use PT lens or any other defish software...or am I missing something, maybe the Photoshop tool DOESN't really work (it did for me 1.3X, but I didn't pixel peep it or compare with other 3rd party solutions or any FF images).
Are you saying you tried Photoshop filter but it wasn't good enough for FF?
I use that for barrel distortion, perspective when I don't use a TS lens---but never have tried it to defish a real FE for a FF. Maybe someone else has.
and not a look I aim for most of the time. I find I'm carrying the 12-24 a great deal. 
