Road Train !!!!!!!!!!

by Russell McMahon

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948 reputation
615
bio website
location ND
age 31
visits member for 2 years, 2 months
seen Aug 20 at 1:38

Dec
22
comment Demosaic data stored in TIFF
@mattdm It's not about programming, nor about image processing methods. The question is asking for a software tool to do something, like many other questions on this site.
Nov
14
comment What is the precise definition of SNR, as used by DxOmark?
That is not my question... It is clear to me why a larger sensor will show less noise when its image is viewed at the same size as the image from a smaller sensor. What is not clear is the precise meaning of the numbers DxO uses.
Nov
14
comment What is the precise definition of SNR, as used by DxOmark?
This is a general definition of SNR, but not the whole story. It doesn't explain why a large sensor with more pixels will have a higher snr than a smaller sensor with the same pixel pitch but correspondingly fewer pixels. The standard deviation alone is independent of the number of pixels for a give per pixel noise level. Please see my comment on the main question.
Oct
1
comment Do official extension tubes degrade image quality?
... not have the same performance for closer objects. This much is clear from physics and geometry. Whether this does have a tangible effect in practice, when one uses an extension tube to allow focusing on objects closer than the lens was designed for, I do not know. The effect may be negligible. I do have a subjective feeling that one telephoto lens I use does not perform as well close to the minimum focusing distance as for distant objects, but that's just a subjective observation that I have never tried to test rigorously.
Oct
1
comment Do official extension tubes degrade image quality?
Image quality is a function of the object distance too though. It is impossible to create a lens that will map any one point (the object) into a single point (image). It's possible to design a lens which maps one particular object point into a perfect image point, but it's impossible to create one which maps all object points into perfect image points instead of smudges. (Think about mirrors: for objects at infinity you need a parabolic one, for closer objects you need an elliptic one.) So theoretically if a lens is optimized for objects beyond a certain distance, it may ...
Sep
19
comment What are some Chinese/Asian photo sharing websites similar to Flickr?
@Alendri And even when/where it is not blocked (it changes from region to region within China), it is simply unusably slow, like many other non-Chinese sites.
Sep
13
comment Demosaic data stored in TIFF
@PatrickHurley I have a single channel which looks like no. 2 here. I'm looking for a tool that'll reconstruct no. 4. I'm not looking to implement it myself.
Sep
13
comment Demosaic data stored in TIFF
Use case: same as here.
Sep
12
comment What Windows software can assemble a sequence of photos into a timelapse?
ffmpeg can do this. It's a command line program that works on all major platforms, including Windows. I have used it on Windows to assemble a time lapse. It's free and relatively easy to use (compared to other command line alternatives).
Sep
7
comment Canon 70-200 f2.8 non IS or f4 IS
Take a look here and here
Sep
5
comment Does shooting RAW vs JPEG have a significant effect on battery life?
You don't lose quality by shooting JPEG. You only lose some flexibility of adjustment. Since the result is downscaled anyway, even a small size JPEG is good enough.
Sep
5
comment How does software raise exposure in post-processing?
@Octopus There are no separate channels in RAW sensor data. What you get from the sensor looks like the 2nd picture here. In a RAW converter exposure compensation would be applied before demosaicing, using a formula similar to yours. As I said, your formula is simply incorrect if you apply it to RGB values. It's only correct for (linear) raw data coming form the sensor.
Sep
4
comment How much does a camera move in 1/250 of a second?
The shutter speed needed to avoid motion blur will depend on the focal length of the lens. With a telephoto lens even a slight movement translated to very visible shake in the viewfinder. The guideline I've seen most frequently is to use a shutter speed 1/2f with a lens of focal length f. Thus with a 30mm lens 1/60 s should be rather safe to use.
Sep
4
comment Portable tripod recommendations for those on a budget
@dpollitt I managed to borrow a Benro A0690T today (~$150), I'll try it during the week to get an idea about what compromises I'd be making with this model exactly.
Sep
4
comment Portable tripod recommendations for those on a budget
@DanWolfgang It still seems like most vocal people here are simply not interested in cheap tripods, as they consider them equally bad. That's okay, but I find it unfair to close the question just because of that. There are quite a few options below $100, and many below $150. I'm sure they're not made equally so for those who can't afford sums matching a U.S. salary the discussion is not at all irrelevant.
Sep
2
comment Portable tripod recommendations for those on a budget
@dpollitt ... this particular cheap tripod and it has these particular faults which prompted me to get a better one". All I see is people echoing that "you need to spend more" on just about every topic, to the point where someone asking advice about his first camera is suggested to spend several thousand USD because he mentioned "weddings and picnics". My past experience with other items makes me very skeptical about these opinions. What I'm looking for is opinions and experiences from people who have actually tried to use such a budget tripod.
Sep
2
comment Portable tripod recommendations for those on a budget
@dpollitt Here's one and another one. I find that the mentality that you need the most expensive of everything even for the most basic tasks is much too common in the online photo community, especially among people from certain countries. I don't see any posts saying that "I got ...
Sep
2
comment Portable tripod recommendations for those on a budget
Do you have one of these two, and if yes, can you give an opinion? According to the specs, folded it's 47 cm, so it's still quite large. I'd compromise on weight sooner than folded length.
Sep
2
comment Portable tripod recommendations for those on a budget
(The gorillapod is a good idea though, I saw it mentioned, and it's my fallback option.)
Sep
2
comment Portable tripod recommendations for those on a budget
There do exist options that meet the requirements I posted, but I'm not sure what exactly I'm compromising on with them. I didn't post particular links because I wasn't sure people here would have experience with those exact models, and what I'm primarily looking for is first hand experience. I'll post some links after I get home from work.