RAK wrote:
Me thinks that is called Bi Lateral Knee Replacement. If the pain in my joints are correct. I am 62 and they did not want to both at once but i said I would not go thru two recoveries. So I have converging lateral lines I can shoot from any time I want. If your wife had both done at once my hats off to her and you better mind your P&Q's cause she is one tough lady to do that and when she recovers you wont be able to out run her around the dinning room table. And as Buzz Light Year said from here to infinity, and beyond. Just keep working on it down load frequently examine and make adjustments until ya git it rite.
Me thinks that is called Bi Lateral Knee Replaceme... (
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Whatever you are on, please can I have some?? 8-) :shock: :)
lighthouse wrote:
Ah yes, but what if the universe is really a mobius strip.
I want the lens anyway.
I think your comments on accuracy in manufacture are right, together with the expansion thing. I have used a number of pairs of binoculars, and the cheaper ones always seem to have more "play" at the infinity end of the focus, and certainly a lot more than camera lenses.
bunuweld wrote:
We are getting into the mysterious land of astrophysics. I will quote myself from a previous post on the subject.:
<<<<And it ultimately astrophysics drives us beyond infinity and into the black hole. This is clearly explained by Cornell University as follows:
<Our high inflow solutions are very similar to the standard Shakura & Sunyaev (1973) results. But our low inflow results are to zeroth order the stationary Papaloizou and Pringle (1984) solution, which has no accretion. To next order in the small, assumed viscosity they show circulation, with disk and conical wind outflows almost balancing inflow. These solutions are characterized by hot, vertically extended disks, and net accretion proceeds at an extremely low rate, only of order alpha times the inflow rate. Our simulations have converged with respect to spatial resolution and temporal duration, and they do not depend strongly on our choice of boundary conditions.>
http://arxiv.org/abs/1206.4059I hope this clarifies the issue :)>>>>
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I understood that the universe is a giant torus = donut shape, and all straight lines go round the torus and join up again. So if you have a powerful enough lens and enough time to wait you would look through it into space and see your own back. Now that would be a lens worth saving up for...... (Do you think there is a cheaper Sigma version??)
wlgoode wrote:
Viewfinder adds stability. Holding a camera at arms length makes it unstable, A close in hold with two crooked arms against the body and pressed against the face makes a camera much more stable. Also today's camera is much lighter than yesteryear's. Though lower mass certainly has its place, more mass gives more inertia which makes a stationary camera more stable. Give me my DSLR, more stable, bigger sensor, lighter than yesteryear's by a fair bit.
I don't go for the bit about yesteryear's SLRs being heavier. My Nikon EM + 50mm series E lens (which I thought was a magic combination at the time) is MUCH lighter than my D600 + kit zoom lens. OK, so am not comparing like with like, but it is what I carried then compared with what I carry now. Do resent the extra weight? Of course not. (If someone has already said this, then my apologies, I have not read all 10 pages!!!! 8-)
mikegreenwald wrote:
Michael G: Can you explain why aperture priority is preferable?
Excuse me butting in again. In order for the software to function properly, you need exactly the same picture content in all the exposures. Hence use a tripod, and you also need the same depth of field in all the exposures. If you change the aperture you change the depth of field, so it is best to work on aperture priority, pick an aperture which stays fixed for the whole set. Just change the shutter, and the only variation between them is the exposure.
GaryS1964 wrote:
I shoot RAW. I do this regularly when I want to bring out more shadow information in a single image. However in my experience the end results is not always satisfactory. It depends a lot upon the original image and how much shadow information is available.
Try this experiment. Take a picture of a scene with a wide dynamic range properly exposed for the overall scene. Now take a picture of the same scene exposed for the shadow areas to maximize information in the shadows. Now do some pixel peeping in the shadow areas of each image and see which has more detail with less noise. My guess is you will see more shadow information with less noise in the image exposed for the shadow areas. This information is brought into a true HDR image. The first image can't possibly bring in that amount of clear shadow detail. At least that has been my experience.
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Yes, exactly. And at the highlight end of the spectrum the cause is different, but the end result is the same. In your average exposure there is more information in the RAW data in the highlights than in the shadows (see the various discussions around on the subject of "expose to the right") until the point where you blow the hIghlights. The underexposed one will capture further detail from the highlights, and bring it into the HDR composite.
marcomarks wrote:
If you're always using the laptop and desktop on the same wi-fi network in your home, you can buy a network hard drive that plugs into your router and all computers, or specific select computers, in your home can access the drive.
Is that secure? And does it need heaps of software installed on the computers? And does it work reasonably quickly? And if so, please can you recommend a make etc. Thanks
So, my conclusion is that you have created fine images, but they are not HDR.
If you don't believe me, find a scene which blows the highlights and loses the shadows and try your process. You won't get it to work. Then try a set of exposures and combine then with HDR software and see the difference.
Here is my lees technical take on this. If you can capture the tones In a scene, without blowing the highlights or losing the shadows, then you don't need HDR. You capture it in RAW or whatever and port process it until you are happy with it.
If you can't capture all the tonal range, then you take say three shots all closely aligned in view and depth of focus, at different shutter speeds. The normal one gets all the mid tones and loses detail at both ends. The underexposed one captures some more detail in the highlights, and loses more at the dark end. The overexposed one capture the shadows, and blows the highlights and some of the middle. Then the HDR software takes all three and combines them, using information from each, to create an image which could not be captured by the sensor ina single exposure.
You can argue that there is an area in the normal exposure between capturing the shadows and losing them, where you capture them but with reduced tonal information. The overexposure capture these better with a higher number of tones. Similarly at the other end. This information is only kept in RAW. If you use the full bit depth available to you, the software sorts out the parts of each exposure to use in the combination, without us having to have a big discussion about maths. But it won't do it without the three exposures, because the sensor cannot capture the full range in one exposure.
Pseudo HDR mimics this by taking as much information as it can drag out of one exposure at both ends, intensifying both, and recombining them together. This is a bit like turning up the extreme base and treble on the stereo and listening to the result. It may be a nice effect, but is not HDR.
OK, does this make sense?
photoman022 wrote:
Take the UV off when you put on the polarizing filter. Don't keep the polarizer when you don't need it because it does eat light.
That sums it up! The argument about keeping a filter on the front for protection will go on for ever. It sounds as if the OP is using one, and I would not disagree, I do.
Bill Houghton wrote:
I don't think so, my UV filter is for the most part Clear and a single ring, My polarize is two lens that are microscopically etched so as I rotate them, more light is blocked did i mention that they are allot darker then a UV.
I don't think he meant to say that they are the same thing, rather that the polariser is also a UV, so you don't need both.
GoofyNewfie wrote:
I have had a couple of great experiences with the EX line of Sigma lenses a d would buy an EX again, but this in not an EX. Great specs though. One thing I noticed was, along with providing the full-frame equivalent info, Sigma also gives the full-frame equivalent aperture, in terms of depth of field, as well. I think that says a lot about the company.
"Equiv. aperture: f/4.2-f/6 (full format equivalent, in terms of depth-of-field)"
I don't understand that. Surely the aperture and depth of field are the same whatever you mount it on, and don't have an equivalent in the same way as focal length/picture angle?
Cameoblue wrote:
A good friend of mine had this lens and absolutely loved it as his walk around lens. That was until his wife dropped it on their ceramic tile floor. It blew up so bad he did not even consider sending it for repair.
Ouch! I didn't want to know that!
Les White wrote:
Mike's advice is what most pro photo sites recommend
Who is Mike? Please use the quote button!