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31
Lenses / Re: Cheap Canon 300mm or 400mm do I Choose?
« on: March 01, 2013, 12:57:24 AM »
Are you shooting baseball and doing it mostly in the daylight? Go with the 400mm f/5.6. It will do much better for baseball outdoors.

If you want a general purpose lens, then the 300mm with IS and f/4 would be better. But there is no way to get the same reach out of the 300mm f/4 lens without reducing the image quality significantly below the quality of the raw 400mm lens. In terms of megapixels, the 400mm lens offers about 77% higher resolution at the same distance compared to the 300mm lens, plus a slight sharpness advantage on top of that.

However, unless you are desperate now is probably not the time for either one. I have a feeling that at least one of them will be replaced, perhaps both, with new and much improved versions.

32
Third Party Manufacturers / Re: Nikon 7100 has been anounced
« on: February 21, 2013, 03:09:59 PM »
Update: this does sound off-topic, but I wrote it to respond to the conflict that was beginning about the "color palates" of Nikon vs. Canon, a conflict that is fundamentally flawed.

The "color palate" of cameras, lenses, and LCDs which I hear about so often is a figment of photographer's imaginations. The only thing a lens has to do with color is separating between color contrasts (low chromatic aberration). The only thing a camera has to do with color is its AWB. The only thing an LCD has to do with color is its calibration (and color spectrum coverage); miscalibration might result in the color being displayed improperly during playback but has zero to do with the actual image, as someone correctly noted by distinguishing between the LCD and the monitor (although the monitor might also be calibrated improperly).

By setting the white balance manually, using both axes that Canon and Nikon make available, not just a one-dimensional Kelvin scale, you can make the colors perfect in the actual image that is recorded digitally. (The reason there are only two axes but three colors is because the third color is determined by exposure, so it is only necessary to control with two variables the proportion between the remaining colors. It is just like the degrees of freedom in statistics, which for a one-sample student's t distribution is one less than the number of data points.)

There is no such mysterious thing as one brand of lens having "warmer colors" or all this other nonsense. Colors are a completely relative thing with digital photography, and even the RGB simulation of color is just a representation of the color spectrum which is actually an interval of the wavelengths of light. RGB colors are unnatural compared to sunlight, and it is just a blessing that our eyes and brains are complex enough to create the illusion of full color from a mixture of RGB.

So since colors are completely relative and white balance completely controls them (except for chromatic aberration), there is simply no such thing as a color palate of a camera or lens, or anything else.

The only thing that might be partly true to say is that the AWB doesn't work the way you see things with your eyes. But that's what you deserve if you are using AWB anyway--it gives someone else's interpretation of color rather than your own. If you want your photography to be determined by the color tastes of an engineer in Japan, then go ahead and use AWB.

And even then you can't blame AWB, because AWB can be fully adjusted so that it delivers your color tastes but still automatically adjusts for different lighting contexts (within the imperfect limitations of technology to detect such things properly, of course).

It's just a shame to see people believing that cameras have "color palates," when it is actually fully under the photographer's control.

Even among professionals, those who are willing to learn to get color right are in the minority. I see so many "great" pictures that are just terrible because those who processed the RAW files don't know anything about white balance, and because the photographer didn't do their job on site to set (or even take any photos of subjects that would have provided the needed data for) the proper white balance.

For example, there was a photo of a bee and sunflower on here. The white balance on that was not quite right. I have done extensive sunflower photography jobs and know quite a bit about it. The bee was OK, but not the background and colors. (I shouldn't judge this though. On the original user's monitor they may have been perfect, but on my precisely calibrated screen they were considerably off.)

P.S. The way to assess "perfect" white balance as I alluded to, is simply to hold a print from your photo next to the original subject. If the colors are not the same, then the white balance is off.

33
Canon General / Re: The need for backup equipment for paid jobs
« on: February 06, 2013, 11:44:43 PM »
Failures are a fact of life. You name it, and it will happen to you. I've had shutters go bad all the way to opening a case on the last day of baseball to find out that an element had come loose in one of my 300mm lenses.

Assume that at least two things will break, and plan accordingly.

34
EOS Bodies - For Stills / Re: New MFA method
« on: February 04, 2013, 03:16:35 PM »
What's even cooler about this method is that the sensor is used only once, at the very beginning. The imaging sensor isn't even used when performing the phase detection AF afterwards.

In contrast, using live view continuously as with FoCal, etc., slowly warms up the sensor and increases the noise and decreases the live view focusing accuracy.

So this method should give maximum accuracy, although it all is dependent on not bumping or vibrating the lens when flipping the switch to manual focus after the first live view photograph is taken.

35
EOS Bodies - For Stills / Re: New MFA method
« on: February 04, 2013, 01:43:54 PM »
Pure genius.

This is something so simple that even the camera manufacturers should be able to program it into their firmware.

Now wouldn't that be nice... just point the camera at a target at the distance where you wanted AF fine tune to be optimized, and press a button which would do this procedure instantly and electronically. You could even re-tune your cameras for a new distance (i.e., when shooting from the back row vs. front row) in real time on the job.

I'm definitely trying it. Why didn't we think of this before? It's so obvious.

36
Lenses / Re: Resistance to Larger Filter Size, Kills Great Lenses?
« on: February 04, 2013, 01:36:28 PM »
Image quality is affected by filters depending on the quality of the filter and on the surface area of the filter.

The larger the surface area of the filter, the greater the reduction in image quality. (You can see this with a softening filter--when your lens is stopped down, the effective diameter and surface area of the filter are reduced. When the surface area goes down, the image quality goes up, and hence there is less of a "softening" effect from the softening filter at smaller apertures (large f numbers).)

A filter with twice the diameter has four times the area. Large filters are bad in this way.

But ultimately, it is due to the expense--the larger the filter, the more expensive it is to make one the same quality as a smaller filter.

In fact, achieving that same level of filter quality isn't enough because even at the same level of filter quality the image quality will still be worse because of the larger area.

37
Canon General / Re: Why did you choose Canon?
« on: January 27, 2013, 05:16:07 PM »
I chose Canon because some of its lenses are unique and I wanted to use them.

I also choose Nikon for the same reason.

I use both systems almost equally, although most of my sports work is done with Canon.

38
Let us say that you have a APS sensor 24Mp with the same S/N as a  24Mp 24x36 sensor then it is an optical question, it is hard to make a APS  lens 1,5 1,6 times better which is require compared to 24x36mm lens.

This is incorrect.

Because there will be less absolute magnification for a same-sized print with the larger format, even if the sensors have the same pixel dimensions, the larger format will be sharper and have less noise. Again, always assuming all else is comparable, including a longer focal length lens for the larger format.

Cheers,

b&

Assuming M.R. means signal to noise ratio by S/N, then he is correct. Actually, the linear resolving power of the lens needs to be increased by the crop factor, and the absolute resolving power of the lens needs to be increased by the square of the crop factor. But this is all based on an imaginary hypothesis, an APS sensor with the exact same S/N ratio as full-frame. Anything is true if the hypothesis itself is false.

39
EOS Bodies / Re: 5D3 Volleyball Weekend and General Thoughts
« on: January 13, 2013, 10:56:01 PM »
Cool, that's nice! I've had some errors, too.

40
EOS Bodies - For Stills / Re: Reikan FoCal Pro with 40 STM
« on: January 13, 2013, 10:16:02 PM »
When shooting with live view, image quality degrades as the sensor heats up. This is just a guess as to why the first lens might be producing excellent results, and following lenses poorer results

Another issue is that you need to place the target closer with the 40mm lens than with the 70-200 because the AF sensor needs a sufficiently large target relative to the field of view of the lens. Usually it is positioned at a distance that is a fixed multiple of the focal length, like 50x (which would be 2000mm or about six and a half feet).


41
Sell it for $600 while you still can. I sold mine last summer for $700 and was lucky. The money is worth a lot more when applied towards a new camera because the new ones are twice as good. The 60D is great, but I'm still sure I made the right decision, and now I have a 6D in its place.

42
ppi doesn't affect the actual image data in the JPEG file. It's just a flag to tell a printer or other method of rendering what dimensions you want the image to have.

For instance, let's say your JPEG is 3000 pixels wide.

If you set the ppi to 300, then you are specifying the image to be rendered 10 inches wide.

If you set the ppi to 200, then you are specifying the image to be rendered 15 inches wide.

But in both cases all the actual image data in the JPEG file is exactly the same.

What does affect the image data is the compression strength, smoothing options, contrast, and other settings you choose while processing the CR2 file.

JPEG is a called a "lossy" compression algorithm because it is almost impossible to use it without losing a tiny bit of data. But the data that is lost begins with image information that is invisible to human eyesight, and then progressively gets more and more visible. That is why JPEG is so effective, because it compresses things that are not visible to human eyes to begin with, and only with significant compression can our eyes actually begin to see a difference.

Storing a JPEG at 100% compression takes far more space than storing at 95%, but the resulting image is impossible to distinguish, assuming that all the processing settings like sharpness and contrast are the same.

The important thing is to never re-compress your original JPEG images, because an additional 5% of quality may be lost if you do that.

I am attaching a file that shows a JPEG that was re-saved (and re-compressed) 100 times. Even though the lowest quality setting was 86%, as you can see, the image has been degraded terribly.

I also suggest using a somewhat lower contrast setting for your JPEG images in order to retain as much detail in both highlights and shadows.

43
One thing I have found to watch for if I want maximum quality at the same time as reducing resolution, is to use small integer ratios, like 2/3rds or 1/2. For example, if my original image is 3200 pixels wide, then I could scale it by exactly one-half and get 1600 pixels wide. The result is much, much sharper and better quality than anything close to 1600 but not exactly 1600. For instance, scaling it to 1700 would actually reduce the quality worse than scaling it to 1600, if the original image was 1600, due to fudging and interpolation needed to produce a pixel matrix that are is not the ratio of simple integers multiplied by the original image.

You can see this visually if you are looking at an image at 100% and then scale it down a few percent. Suddenly the image gets softer, but it will get sharp again when you are at a ratio that is a simple ratio of two small integers like 3/4, 1/2, 2/3, etc.

If you are keeping full resolution, then this won't matter. (It sounds like the OP just wanted full size images, but the second poster talked about downsizing.)

Also, if you are scaling down by more than a 5:1 ratio or so, then it doesn't matter what scale you choose because there are so many pixels to choose from that fudging and interpolation doesn't end up making the image softer. So an image that is 320 pixels wide will be just as sharp as one that is 317 pixels wide, if the original was 3200 pixels wide, for example.





44
Lenses / Re: 5D3 + 135mm F2
« on: December 31, 2012, 08:15:07 PM »
great to hear that.  Thanks a lot for your sharing.  With my 50L experience and reading people complain about 85L. I am really hesitate...

The 135L outclasses both the 50L and 85L with regards to AF issues.  Not in IQ certainly, but with AF issues.

I'm not sure what you mean by "Not in IQ certainly." The 85mm is good, but the 135mm is better. Even when the 85mm is stopped down all the way to f/2.0, the 85mm is only barely sharper in its dead center (that's being compared to the 135mm when the 135mm is still wide open.)

The 50mm L is not even close. Its lack of sharpness has always been regarded as a big disappointment for such an expensive lens, and everyone has been awaiting a revision for quite some time in hopes that IQ will improve.

Here are some data that illustrate that the 135mm is as good or better than both of those lenses, even when it is put at a disadvantage of being shot wide open and the others are allowed the advantage of being stopped down more than one stop under their maximum aperture.

Additionally, CA and other aberrations are more controlled with the 135mm.

Units of resolution are resolvable line widths per picture height (LW/PH).
135mm L @ f/2.0 (wide open): Corners 2746, Center 3306
50mm 1.2 L @ f/2.0 (stopped down): Corners 1472, Center 3051
85mm 1.2L @ f/2.0 (stopped down): Corners 2425, Center 3472

For me, if anything, it is actually the focusing speed of the 135mm L that I wish would improve. Sometimes it's not quite there, when compared to the speed of the 85mm 1.8 or the 70-200 mm II.

I would be willing to pay $1,000 extra dollars to have a 135mm f/1.8 that had an extra 1/3rd stop of aperture plus truly modern focusing speed. That's not even thinking about IS, which is basically irrelevant to me since I use my 135mm lens 90% of the time to stop action, where IS is not a factor.


45
Lenses / Re: 50mm upgrade or 85mm coverage?
« on: December 31, 2012, 08:01:04 PM »
Someone mentioned that the Canon 85mm 1.8 has more unreliable autofocus. I am just posting to say that I have not found that to be the case. The Canon 85mm 1.8 has the best autofocus on any possible lens that I have tried, better for sure than the 70-200 II, for instance. It's never unreliable unless user error causes it to be so. (I.e., you mis-place your focusing points, such as accidentally beginning to press the button before the AF points are actually on your desired subject.)

The Sigma 85mm f/1.4 has slightly unreliable autofocus, I have found, but good enough that I can still rely on it at a basketball game (not 100% reliable). But Sigma's image quality at f/2.0 is far better than the Canon just because of the CA problem (chromatic aberration) that the Canon has.

With the Canon, you will get purple reflections from the out of focus stadium lights reflecting off of glasses, for example (ruining an otherwise good dunk photo, for example) if you shoot below f/2.8. So basically you are wasting more than one stop of the len's potential in order to avoid CA.

I don't have to worry at all about CA with the Sigma lens at f/2.0.

CA is the problem with the Canon, but its auto focus is as close to perfect as possible on all of my copies and every else's that I know. So I had to chime in and say something.

Yes, I have had disappointing focus experiences myself, but it has always been user error of my own like getting too eager and starting to lock focus before a subject is close enough to even register on the AF sensor. If I make a mistake like that, the lens will do a perfect job of tracking focus on the background. The way to fix that mistake is to take my finger completely off the shutter and re-acquire focus on the proper subject. So if you are experiencing any focusing problems with the 85mm 1.8, just wait a little bit. AF takes technique from the photographer as well as capability and accuracy from the lens. I am still learning and improving every day.



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