Hot answers tagged calibration
35
What you're looking at through the viewfinder is actually the image from the lens projected onto a ground-glass viewing screen. You want the diopter to be adjusted so you can see that most clearly.
Fortunately, this means that you can use the etched lines on the focusing screen, as well as the status information in the viewfinder, to adjust the diopter. ...
19
In that particular instance, the speaker is talking about the manual focus-by-distance capability. Stills cameras have always tended to be focus-assisted (whether by SLR screens, rangefinders, or autofocus), while professional cinema (and, by extension, high-end video) has been done my measuring tape, marks on the set, and follow-focus for moving subjects.
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16
Ideally, you're shooting in an environment with controlled lighting (a single light source, or several tuned to same color temperature), your subject and black or white surfaces only. In this case, the angle does not matter - just take care that its exposure falls somewhere in the middle in your test shot (so you're not accidentally clipping a channel).
In ...
10
These cameras have microadjustment capability, just not in a user-accessible way.
The exact method varies by model. Some have a software feature in an advanced (and secret) "debug" menu — the Pentax K10D, for example, had this. Others have physical adjustment screws or similar (like earlier Canon Rebel models). Or, repair centers may simply use shims.
To ...
8
Two words: "ambient" and "context".
At the risk of making what sounds like a "No true Scotsman" argument, "real" monitor calibration is always in the context of the ambient lighting conditions. Not only do the pertinent standards (ISO 12647 and related) specify the lighting levels and colour temperatures under which critical colour work should be performed, ...
7
There are several issues related to Phase Detection Auto Focus performance. You first must determine what the source of the problem is. It could be caused by one of several factors, or a combination of some or all of them. If you also have the problem when using the Contrast Detection AF in Live View, then the problem is somewhere else.
Front/Back ...
6
Yes, there is a point. It will let you see your own photos more accurately. Since you do not print them, I assume you look at them on your own monitor.
Even if it is only for others, non-calibrated monitors differ widely but they are improving at least in the mid-range with the advent of LEDs (and eventually OLEDs), so over time people will see your images ...
6
It sounds like you need a scientific imaging device. I was told when I worked with these things that scientific grade CCD imaging devices are the most linear devices known to man, in contrast to the imagers discussed by @Guffa. I'm talking about cameras made by photometrics, pco (the sensicam), or devices made for astrophotography or microscopy.
These ...
5
Generally, sending in both camera and lens for calibration should result in more accurate AF. I would suggest that you first do some focus tests with batteries or focus charts to determine if the lens is back- or front-focusing, or if it is inconsistent AF (indicating a possible USM issue), that way you can verify the results after the lens comes back from ...
5
Take a look at the focus screen in your camera. That actually has the same focus as the object in focus, and it's a lot easier to see. Adjust it until you see the thinnest lines possible, and you are set. Optionally, you can actually remove the lens to do this, as it makes it easier to not be confused by an object in the scene.
5
Your assumption about it being a closed loop may be wrong. I see numerous references to AF systems generally being "open loop". In other words the AF system calculates the amount of movement needed to achieve focus then moves the lens there, but does not recheck. So it may over- or undershoot the target. I could not find an authoritative reference from ...
4
The Pentax K-7 and K-5 have the ability to make basic adjustments to the rear LCD screen on a green-magenta and blue-yellow grid. There's no curves or calibration measurements, so you have to eyeball it, but even still it's a nice feature. I adjusted mine by putting a gray card right next to the screen and adjusting until it seemed to best match (a few ...
4
There are other types of calibration besides focus calibration - one of the elements could be out of alignment causing softness under certain conditions. This could be the result of a manufacturing defect or damage.
This happened to me when I dropped one of my lenses, I sent it to Fixation in London (an official Canon repair centre) and that solved the ...
3
Yes.
Using a calibrated monitor effectively makes your monitor a "control" and the variations found when viewing the images on another display are going to shift it from that control colour and exposure. You want your monitor to display the photo exactly how you want it and the others to only be different due to their limitations.
When you don't use a ...
3
Yes it can be calibrated using the proper hardware. I have a retina display macbook and also a Spyder Elite 3, and I can calibrate it to match my 23" desktop monitor.
The result is pretty close, side-by-side, the colours are almost identical.
Inaccurate default settings of the Macbook
This is true. You were also right about the high contrast. I was stupid ...
3
Yes. This is an autofocus only issue. Front or back focus simply means that the camera focuses the lens in front or in back, respectively, of where focus actually is. This is related to a particular camera and lens combination due to manufacturing tolerances.
The easiest way to see if your camera and lens together exhibit the problem is to perform a focus ...
3
I think that most cameras would work for this, provided that they produce RAW (or DNG) files and that they have manual exposure settings.
If you don't use the RAW format, the image will be processed. This usually means that some curve is applied, and it always means that you lose some information. The RAW format usually has higher data resolution (e.g. 12 ...
2
Not on the 5D II or 1D III according to this: http://forums.dpreview.com/forums/readflat.asp?forum=1032&message=30722960&changemode=1
Before there was microadjustment in firmware Canon would calibrate the lens and/or bodies by replacing the metal mounts. Perhaps (hopefully!) this is still how it's done.
Magic Lantern doesn't wipe your settings.
2
Yes, you should care, as the colors that are seen by your audience can vary surprisingly dramatically. You should attempt to be as accurate as possible, but sometimes it doesn't even matter, especially if the browser your audience uses isnt color managed. These days, this is less and less an issue, as Firefox, Safari and even Chrome support ICC profiles.
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2
The process is similar to screen calibration except that the output is one step removed.
Most products use a software to output a controlled test which is basically a grid of colors. A hardware spectrograph that looks at each square and sends the result back to the calibration software is also needed. This creates a multi-dimensional matrix to map between ...
2
From what I understand, what is being set is a value that is added or subtracted from the position that the camera is instructing the lens (or focus motor in the body for body driven lenses) to move to. So, if the camera would normally say move to "123" and you have a +3 adjustment, it will actually say move to "126" instead. Note, those are made up numbers ...
2
What SHOULD it do
A 35 mm f/1.4 anything stopped down to say f/4 or above and used to take well lit carefully focused closeup of eg a head of hair should produce an image so sharp that you'd cut yourself on the individual hairs.
Put the system in manual focus, put on a tripod and focus on a test target with fine detail. Take photos while moving test ...
2
Wow, there are so many things that can be affected... Assuming there is damage (an 18" drop onto carpet isn't likely to have damaged anything, but it's possible) the most likely situation might be a warping of the lens mount so that the mount isn't parallel with the sensor (either the focus sensor or the main imaging sensor). The focus sensor would focus on ...
2
Does this happen from all applications, or only from colour-management-aware ones, like PhotoShop?
If the latter, you may need to install a different ICC/ICM (colour profile) file for different printer settings - and tell the application to use it. Different paper types also require different colour profiles.
Have a look at this site for more info:
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2
I wouldn't calibrate based on what the print looks like from them. I'd calibrate to a standard. It's going to be really really hard to find a CRT with good color these days as they basically don't exist anymore and most of what you can find is crappy left overs (those who have good CRTs tend to hold on to them).
If you can find a CRT, programs like Adobe ...
1
While I lack direct experience with the Retina display, this article from ZDNet appears to indicate that it can be well calibrated. It also looks like they specifically did tests with a Spyder in that article.
Most likely the issues your photographer friend was experiencing was a gamut issue where the colors being produced on screen could not be replicated ...
1
I think this may be an issue caused by the non-genuine inks.
The Epson photo printers use what they call "Meniscus control" to create variable ink droplet sizes from the single nozzle, by "wabbling" the ink up and down until a small droplet is released. like the little droplet that is ejected upwards from a larger drop of water hitting water.
If the ink ...
1
20mm out is a massive amount and not explicable by any normal calibration errors.
If it is really back-focusing by 20mm (2cm) then something is faulty.
If the D800 is OK with other lenses it's liable to be the lens that is faulty.
BUT If the lens is OK with other cameras it's liable to be the camera.
BUT if both the above apply, which is how Murphy loves ...
1
Unfortunately, the monitor you have cannot be H/W calibrated and I have no idea what it does with its internal LUTs. You have two options at this point:
Return it for a calibratable monitor. My recommendation is the NEC P241W which I own two off (New they are $450 but I about them refurbished for $237) in addition to one of NEC's 30" model (LCD3090WQXi).
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1
Printer calibration is usually done by printing a set of known colors, scanning them in with a known device, and using compatible software to compare the results of the scans against "known good" values that the scanned print colors should be replicating. Scanning can be done with a spectrophotometer, or with a colorimiter. Spectrophotometers are usually ...
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