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Thread: 4/3 DR

  1. #1
    Subscriber Member Jorgen Udvang's Avatar
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    4/3 DR

    I'm kind of a slow person, and it has taken me almost a year to really start liking the GH1. But now when I do like it, I really prefer it to my other cameras, even a day like yesterday, when I was carrying almost 3 kilograms of D300 with 80-200 AF-S from my belt. It became unused to a degree that I forgot that it was there, and almost sat on it on several occasions.

    To be completely honest, I don't even think about the EVF anymore as being different from an OVF. I just use it. It does get a bit problematic when I try to get the menus up in the viewfinder of the D300, but that's because I'm old and my brain is slowly fading away, right?

    There is obviously potential for improvement, particularly in the ergonomics department, but that can be said for most cameras, particularly the smaller ones. High ISO could be better also, but it's really not a big problem. I rarely take photo of the inside of my lens cap anyway, and my hands are, unlike the previously mentioned brain, still rather steady.

    The only thing that really worries me is the dynamic range. It's limited, which I expected, but what is even more problematic is that the blue channel seems to clip way later than the others, giving a cyan cast around highlights, particularly when the gradient to the blown area is subtle.

    In the photo below, which has some extreme contrasts, this becomes very visible in the sky. By making an interesting S-shape in "Curves", I managed to pull out a lot of detail in the shadows and also make the blown sky less blown, but the cyan cast is still there, very obviously so too, and a complete fix would require some elaborate post processing.

    It would be interesting to hear what people do to get around these challenges with 4/3 and m4/3 cameras. That way we may all be able to improve the results from our cameras.

    GH1 with Pana 7-14 @ 7mm and f/5.0. Does anybody know how much heat the front element can take before the coating starts melting away?


    For those of you who haven't yet bought the Panasonic 7-14mm: Just buy it. Sell your car or your wife or a kidney and buy it. It's that good. And if you aren't able to take good photos with it, just the pleasure of comparing size and weight when you meet somebody with a Nikon D3 and 14-24mm is worth the money

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    Re: 4/3 DR

    Hi Jorgen. I usually tried to expose for the highlights, with the GH1, then bring up the shadows, with a little fill in ACR or you could use fill flash. You could use a grad ND filter too, I guess - kind of a pain with anything but landscapes. I've noticed that the GH2 seems to do a bit better though.

    It's hard to beat the size and weight and kind of makes it worth the extra work.

    I've been thinking about the 7-14 for the past year or so, but not being able to put a ND filter on it has kept me at bay and the images I've seen from the little Oly haven't really impressed me too much. I may just cave in one of these days and get the Pany .

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    Workshop Member ptomsu's Avatar
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    Re: 4/3 DR

    Jorgen,

    the 7-14 is absolutely a wonderful lens and one of my next to buy!

    WRT Dr and Cyancast, I think the GH2 is better than the GH1. As is the EVF. So if you like the GH1 you would absolutely LOVE the GH2 I think. At least I did never feel I had too less dynamic range or any specific cast with my GH2 so far (600 shots taken).

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    Subscriber Member Jorgen Udvang's Avatar
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    Re: 4/3 DR

    Quote Originally Posted by ptomsu View Post
    Jorgen,

    the 7-14 is absolutely a wonderful lens and one of my next to buy!

    WRT Dr and Cyancast, I think the GH2 is better than the GH1. As is the EVF. So if you like the GH1 you would absolutely LOVE the GH2 I think. At least I did never feel I had too less dynamic range or any specific cast with my GH2 so far (600 shots taken).
    So the easy way out is to buy a GH2, hack the GH1 and use it for backup and video.

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    Senior Member pellicle's Avatar
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    Re: 4/3 DR

    Hi

    Quote Originally Posted by Jorgen Udvang View Post
    The only thing that really worries me is the dynamic range. It's limited, which I expected, but what is even more problematic is that the blue channel seems to clip way later than the others, giving a cyan cast around highlights, particularly when the gradient to the blown area is subtle.
    Yes, well actually it depends on the light. Perhaps I missed it in your post, but are you capturing in RAW or JPG?

    Back when I got my G1 (of course a different animal to the GH1) I did a little experimenting and found that the recording of data for R G and B channels was not as "linear" as I'd expected. I put some data and discussion up here on my blog.

    What I found was that Green started recording data in the shadows much earlier and that Red and Blue were later ...


    which seems to fit the observation of greater noise in R and B channels when you cycle through them in Photoshop.

    Now if you were recording in JPG then the camera may or may not be doing something more or less cunning but causing clipping.

    thoughts?

    In the photo below, which has some extreme contrasts, this becomes very visible in the sky. By making an interesting S-shape in "Curves", I managed to pull out a lot of detail in the shadows and also make the blown sky less blown, but the cyan cast is still there, very obviously so too, and a complete fix would require some elaborate post processing.

    It would be interesting to hear what people do to get around these challenges with 4/3 and m4/3 cameras. That way we may all be able to improve the results from our cameras.
    So far I've been fond of using Photomatix for some processing. I have just plopped v4 on my system and found it is quite pleasing.

    Now, please don't scream at this set of colour balance because at present I do not have a system which is calibrated (having just moved back to Australia and have had many distractions such as starting new jobs and renovating my house). But for instance this image:

    young Kookaburra by obakesan, on Flickr

    was processed in Photomatix using one of their preset options (with a thumbnail preview) and then the effects softened a little. Subsequent post processing was a quick sharpen and that's it.

    It is in contrast to the camera JPG a whole lot better in colour and shadow detail.

    Processing was fast and simple.
    Last edited by pellicle; 18th January 2011 at 03:25. Reason: rectify stupidity

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    Subscriber Member Jorgen Udvang's Avatar
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    Re: 4/3 DR

    Thank you for very useful information, Pellicle. In danger of sounding like one of the totally uninformed: What do the numbers in the "A" column represent?

    I'm shooting jpegs plus RAW at the moment, but I haven't got a version of my preferred RAW converter, ACR, that can read the GH1 files, and I haven't really got on friendly terms with Silkypix yet. Photomatix may be an interesting option, but again, there's probably a learning curve. Time to upgrade, I guess.

  7. #7
    mco_970
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    Re: 4/3 DR

    Hi,

    For processing, when I was using G1 (HATED the blues on that camera), I downloaded an X-Rite color checker profile someone had made for G1 and used it with LR3 as a preset to develop RAW files and it helped a great deal with blues. I am still using the same preset for GH1 :-) since I have not found a proper GH1 profile. I should buy the X-Rite system, I know... Anyway, I think that will easily help deal with the cast in processing.

    For shooting, what may help is to set your JPG contast to LOW and watch your histogram when you shoot. The histogram is based on the JPG you shoot, and setting contrast to low makes it MUCH more accurate as to where the clipping point is. There is info on Luminous Landscapes about why this is. Similarly, I really have to watch the red channel on my 7D and setting contrast low on it really helps to not clip it when shooting things like flowers.

    Cheers,
    Michelle

  8. #8
    Senior Member pellicle's Avatar
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    Re: 4/3 DR

    Quote Originally Posted by Jorgen Udvang View Post
    Thank you for very useful information, Pellicle. In danger of sounding like one of the totally uninformed: What do the numbers in the "A" column represent?
    pardon my detail bleak responce ... I am not sure its even spelled out well in the blog post. As you may recall digital assigns numbers to represent the level of light it records for each pixel. This is done in steps from 0 (what the camera calls dark) to 255 (in an 8 bit world). The col A represents those steps. 2 to the power of 8 is 256, and a 12 bit number would be 2 to the power of 12 which is 4096.

    As you can see the camera is giving 12 bits of data but is not properly tuned to optimally sit the capture of analog in the 12 bits available to it. The least significant 3 bits of data are hardly used (although they contain little meaningful data) and are irregularly used ... supporting the observation that there is buckets of noise in the shadows.

    I'm shooting jpegs plus RAW at the moment, but I haven't got a version of my preferred RAW converter, ACR, that can read the GH1 files, and I haven't really got on friendly terms with Silkypix yet. Photomatix may be an interesting option, but again, there's probably a learning curve. Time to upgrade, I guess.
    Silkypix has no friendly terms ... Photomatix is so insanely easy to come to grips with you'll wonder why you didn't try it. It is aimed at HDR work, but does mighty fine at tone mapping (which is what a simple curve essentially is)

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    Re: 4/3 DR

    I've now spent a lot of time working with Olympus E-5 raw files, Jordan. One of the things I've discovered is that the standard default settings for the E-5 raw files in Lightroom (and Camera Raw) are too aggressive on contrast, brightness and sharpening for best results. I think this is the result of its very weak antialiasing filter and LR/ACR 'standardized' defaults which seem to be applied to all cameras' raw files.

    I've created pre-sets that provide a more sensible starting point, knocking back black point, brightness and contrast to 0 and setting a more modest sharpening setting with a high mask value as a starting point.

    The result is greater dynamic range and much nicer tonal values. Micro-gradations in the Zone II-IV range are cleaner, the appearance of noise more subdued. I see about a stop and some more DR to work with ... that's up around 11.5 stops by my informal testing ... without loss of detailing.

    The same technique might be useful for G1/GH1/GF1 bodies too. All of these models have relatively light antialiasing filters and will likely respond to these kinds of alterations to the Adobe defaults on raw processing. You might also consider a customized camera calibration profile if you see asymmetrical channel clipping.

  10. #10
    Senior Member pellicle's Avatar
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    Re: 4/3 DR

    Hi

    here is the camera JPG for comparison ...

    P1100906

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    Senior Member pellicle's Avatar
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    Re: 4/3 DR

    Jorgen

    just whacked this together

    http://cjeastwd.blogspot.com/2011/01...g-and-raw.html

    may help you along on the Photomatix side ... other than that Godfreys suggestion of a profile for the camera is also an excellent one.

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    Senior Member Tesselator's Avatar
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    Re: 4/3 DR

    I notice massive cyan areas - especially in OOF areas too. But here's the kicker, use a different lens and it goes away completely. The 7-14 is especially bad at this. I haven't seen cyan "casting" due to the sensor - I have only seen it from various lenses or bad WB. Some lenses are worse than others. The 15mm SMC Takumar f/3.5 fisheye is another one like this. It has much better colors overall than the Lumix though. There are many many lenses in the 35mm to 85mm range that suffer this problem. People who claim to know just call it CA - so I do as well. The fact that some other lenses do not display this when shooting the identical scene tells me that it's lens based and not to do with the sensor.

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    Senior Member pellicle's Avatar
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    Re: 4/3 DR

    Quote Originally Posted by Tesselator View Post
    People who claim to know just call it CA - so I do as well. The fact that some other lenses do not display this when shooting the identical scene tells me that it's lens based and not to do with the sensor.
    yeah ... my FD200f4 is a sweet little lens, but my FD200 f2.8 has significant CA as you open up ... both at 5.6 are lovely

    I guess that is why lenses like APO are more expensive ... its hard to correct this aspect of optics.

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    Senior Member Tesselator's Avatar
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    Re: 4/3 DR

    cool image!

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    Subscriber Member Jorgen Udvang's Avatar
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    Re: 4/3 DR

    Pellicle and Tesselator,
    Great and very helpful information. The CA theory is interesting, and would indeed influence how the problem can be solved. Now I have to go out and test different lenses to see how the colours are affected around highlight areas.

  16. #16
    Senior Member Tesselator's Avatar
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    Re: 4/3 DR

    I just posted some 100% crops of this lens (the Lumix 7-14) in the other thread. there's a few images that reminded me of this discussion.








    While I didn't have another UWA lens with me at the time I'm reasonably certain that something like my Nikkor 16/2.8 ED ($500) would not have rendered these with all that cyan in there.

  17. #17
    Senior Member pellicle's Avatar
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    Re: 4/3 DR

    Quote Originally Posted by Tesselator View Post
    I just posted some 100% crops of this lens (the Lumix 7-14) in the other thread. there's a few images that reminded me of this discussion.
    ahhh ... looks like the insides of a Japanese camera shop ... memories


    sigh

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