[Brightcolours]

Wellno, with a 5DS or 5DSR you will not get softer corners than with lower resolution cameras. In same print sizes you will get more sharpness in the corners, and in extreme cases the same sharpness. Never softer, though.

[davidmanze]

  Ambiguity....... the enemy of science!

 

 

 

There is a difference between the terms..... softer/sharper (appearance)....  and more or less detailed. (resolution)

 

In my view the latter is correct or at least appropriate to technical discussions on optics here,......... 6 MPs sensors could could produce sharp images (ie.crisp edges)........ but could not resolve high detail content.

 

Modern 42 Mps sensors are high resolution capable and can therefore can produce highly detailed images, not always so detailed using lower resolution optics.

 

 IMHO The words sharpness/softness are not the terms we should be applying to modern imaging..........high /low

 

detail/resolution are the only terms appropriate in this modern era, otherwise that's where the confusion arises.

 

   Unless of course we want to chat about the old days of 4Mps sensors!

[JJ_SO]

Lensrentals took the can opener again, this time the Sigma

 

Roger complains about missing adjustment elements. I think, Sigma decided to go electronically in terms of adjustments. It's very easy to bring Foveon sensors behind the lenses and adjust them by writing the values into the firmware of the lens. Best of it, that can be done with a high amount of automatization.  ^_^ It's like AF Micro-adjustment on fully automatic.

 

But if the lens is not centerred, it has to go back to the work bench.

[davidmanze]

The Sigma looked good to me.....just a question of checking for de-centering after purchase and returning for another if it's not good.

 

 The construction levels are way above some of the old EX series lenses..........

   I've stripped down an old  28-70 EX F2.8 and to be quite honest the construction was not far away from just plain cheapskate.....many self tapping screws into plastic........and not much in the way of metal..... the old AF screw-drive pinion drives direct on to the inside of the lens barrel where the teeth were just part of the barrel moulding.......with no manual AF provision, inadvertently holding the barrel in AF mode easily strips the gears and is too easily done....which is what had partially happened.  Add to that a super thin rubberized outer coating which was falling off and all in all there's nothing to justify their EX category.

 

 Their new upgrades in optical performance has been followed through in the mechanic revision of their lenses.....very nice too! 

 

Lens Rentals really are giving us a thorough insight into the build as well as the optic consistency of lenses, which is really great, without that it would have been (and I must admit I am guilty of it myself) all to easy to think that the Canon 35mm  F1.4 was way overpriced,  but in fact it shows by how much their construction goes beyond the call of duty!

[Rover]

The Sigma looked good to me.....just a question of checking for de-centering after purchase and returning for another if it's not good.

 

 The construction levels are way above some of the old EX series lenses..........

   I've stripped down an old  28-70 EX F2.8 and to be quite honest the construction was not far away from just plain cheapskate.....many self tapping screws into plastic........and not much in the way of metal..... the old AF screw-drive pinion drives direct on to the inside of the lens barrel where the teeth were just part of the barrel moulding.......with no manual AF provision, inadvertently holding the barrel in AF mode easily strips the gears and is too easily done....which is what had partially happened.  Add to that a super thin rubberized outer coating which was falling off and all in all there's nothing to justify their EX category.

 

 Their new upgrades in optical performance has been followed through in the mechanic revision of their lenses.....very nice too! 

Well, then was then and now is now... that lens model is from the iron age! I almost ended up buying one 10 years ago. Glad I skipped on it - it was way before even cheap lenses started becoming pretty good.

By the way, I have a Sigma EX lens from that era - or even older, because it's not even marked DG - and it's pretty good with metal outer construction (no idea about the inside - I'm smart enough to never try disassembling anything, since I got a veritable hand of thumbs!) and HSM focusing (pretty fast and silent, but not entirely accurate). I'm talking, of course, about the good old 14/2.8. So the EX lenses were not all born equal either... (I truly shudder to think what the non-EX ones were like back then...)

[davidmanze]

  Yep the EX range were a mixed bag..... I've the 50-150mm F2.8 EX HSM in the PK mount and feels very solid (also excellent optically) as well as 10-20mm F4-5.6 EX (screwdrive) in the PK mount,  but they were after the 28-70mm F2.8 and I think even then they were trying to shed their earlier reputation.

[Rover]

Well, the 14mm is a known diamond-in-the-rough. It has a lot of flare and pretty soft edges (unless you stop way down - even on a Canon 1D series) due to strong field curvature, and the AF is sometimes confused (I guess it can be explained because a lot of shooting involves vast distant objects with small detail, as opposed to a well defined central subject that is easy to lock on to). But I'm pretty sure the Arts are an altogether different matter yet...

[Brightcolours]

http://dustinabbott.net/2015/12/canon-ef...sm-review/