Simone S
Leading Member
It's not a low res...if you click on the picture you can go to my gallery page and see the 100% crop from the original 42Mp file i posted.
-
Welcome to the new forums! Please read this first. For known issues we are working to resolve, click here.
ZOIP
Member
Not sure how it will go for your flowers, the filtration needed etc is very much camera dependent, are you using a Canon, from my experience they seem to be particularly sensitive to that magenta explosion, but I sold my last Canon 12 months back so I couldn' t check to let you know if thats the case.
As an aside one of the most significant benefits is for times when you want to channel mix for monochrome purposes, with an even colour noise ( pretty much noiseless) signature you can mix without any worry about noise variations occuring across the image dependent on the donor tones original colour, plus as I said the files are very flexible. The effect on the A900 is quite extraordinary mainly because the red channel is pretty much always underexposed under normal shooting.
As an aside one of the most significant benefits is for times when you want to channel mix for monochrome purposes, with an even colour noise ( pretty much noiseless) signature you can mix without any worry about noise variations occuring across the image dependent on the donor tones original colour, plus as I said the files are very flexible. The effect on the A900 is quite extraordinary mainly because the red channel is pretty much always underexposed under normal shooting.
ZOIP
Member
Ok sorry the link didn't show up initially, odd. Anyhow to me that looks like jpeg compression artefacting, possibly exacerbated by heat haze and it could be lens related due to magnification, lens coatings, actual resolving power of the lens, but honestly its pretty hard to tell from just a single image. i probably not being that helpful.
Simone S
Leading Member
Thank you for your attention by the way...
It is happening only with focal lengths over the 135mm but i can see it with every kind of weather so i don't think it is connected with haze...and my Nikon in the same conditions does not show anything similar!
It is happening only with focal lengths over the 135mm but i can see it with every kind of weather so i don't think it is connected with haze...and my Nikon in the same conditions does not show anything similar!
Can you point to what in particular you think is wrong with the image, because all I can see is heat haze and lots of it...
It's common when using longer focal lengths to see this, and it doesn't have to be that hot, it's caused by temperature differences in the air.
Water often looks posterized, even from film.I am so far very happy with my A7RII but this discussion and Lloyd's picture did give me the incentive to review images I made with large bodies of water. This particular image was taken with the A7RII and an old but excellent condition Takumar 28mm 3.5 . I opened the raw file in PS and applied a small amount of distortion correction...nothing else...the OOC Jpg looks nearly identical...I'm not sure how to describe the effect in the lower left corner, is this posterization or something else?
100% crop
Ignoring the coarse granularity, note the areas of apparently flat tone.
ZOIP
Member
Yep I just had a further look at it, this one is at 300mm so the DOF is actually quite shallow which lowers the contrast in the more distant parts and makes the haze look more pronounced. With long teles heat haze will effect the image even at 20 degrees and even in cloudy conditions. Additionally it looks worse around the left hand side building, but the surfaces of the structure would be bouncing a fair amount of heat off the walls fuzzing things up a bit more as expected. jPEG compression also makes hazy images look worse, even when you use the best settings.
Try shooting some raw files and comparing the results, I can vouch that with every Sony I have tested there is a chasm of difference between how the details render in JPEg and what is possible via a really good raw convertor.
Try shooting some raw files and comparing the results, I can vouch that with every Sony I have tested there is a chasm of difference between how the details render in JPEg and what is possible via a really good raw convertor.
The Sony A7 series and the Sigma DP_M series are both fine cameras capable of outstanding image quality, but the images they produce are rather different.
I can see that somebody might have a strong preference for one or the other. This is like preferring Kodak to Fuji films.
I don't think any serious current camera "wipes the floor" with any other. There are differences, but they are not really all that great in real life use.
(I would accept that an A7r2 "wipes the floor" with the floppy-disk Mavica.)
Magenta or red ? And do you use 40 or some other density ?
A magenta filter on red flowers will give you more red, so more clipping.
Try a Cyan filter for red flowers. The results will probably depend on the particular flower and on the IR transmission of the filter.
Simone S
Leading Member
Ok,thank you all...the more i look at it and the more i also think it is just the effect of the haze!
Thx for your attention and for your answers!
Simone
Thx for your attention and for your answers!
Simone
Mikael Risedal
Veteran Member
This is not posterization issue it is a color management issue ...
It can be seen in RawDigger is that he drove with semi-mechanical shutter time which halves the bit resolution in the readout. Well documented, should be avoided at base ISO and ISO200. ISO400 and up it makes no difference, the noise is much higher than the lowest quantization level.
Mikael Risedal
Veteran Member
Last edited:
ProfHankD
Veteran Member
Potentially, yes; in reality, I don't think so. Looks like the lake just fell in a sparsely populated portion of the colorspace representation near blue saturation... and that region of the image is also a bit out of focus. Actually, pretty impressive that the image is so even over such a large area! Many cameras and lenses would produce concentric circle artifacts spanning the whole region for this sort of thing thanks to minor vignetting. Actually, somewhere I have a very similar scene shot years ago at one of the ponds with a Canon Rebel XT... and it has exactly the concentric ring artifacts I'm talking about....
I didn't understand that. What is the semi-mechanical shutter time?
Indeed, but the point I was making was he goes on and on about artifacts from one camera, and ignores artifacts from another...
Iliah Borg
Forum Pro
In a selection of water over 1.8 million red pixels, in raw, red channel has only 46 different values; with max= 138 and min= 46. That is, again, already in raw. I looked through my shots on several lakes made with other cameras, and even when using a polarizing filter the number of levels in red channel is about 200 (twice as much, if you consider the range 138-46). That includes a lake with limestone bed, very blue one.
Must mention again, sorry, that if the image would be exposed one stop hotter (and that was possible), the range would be 276-92, closer to what it should be. Now, with a magenta filter nearly a two stop boost of the red channel is possible.
Posterization originally meant using few colours (as it was used when drawing posters) so that a smooth tone is not formed on colour transitions.
As to profiles resulting in posterization; the profiles I use at the raw conversion stage can't cause posterization as they are simple matrix transforms, and the software does not clip. Still, the problem is there, but of course not as dramatic as with uncontrolled transform to AdobeRGB.
Must mention again, sorry, that if the image would be exposed one stop hotter (and that was possible), the range would be 276-92, closer to what it should be. Now, with a magenta filter nearly a two stop boost of the red channel is possible.
Posterization originally meant using few colours (as it was used when drawing posters) so that a smooth tone is not formed on colour transitions.
As to profiles resulting in posterization; the profiles I use at the raw conversion stage can't cause posterization as they are simple matrix transforms, and the software does not clip. Still, the problem is there, but of course not as dramatic as with uncontrolled transform to AdobeRGB.
exdeejjjaaaa
Veteran Member
so you never ever use LUT profiles in your raw conversions (I mean the regular commercial work) ?
Similar threads
Keyboard shortcuts
- f
- Forum