OT: the new Olympus E-M1 in low light (was: Re: Aliasing question)

2013-10-12 Thread Godfrey DiGiorgi
The new Olympus E-M1 arrived yesterday. I picked it up on the way to the office and charged the battery there. My first test of it after I got home from the office was to stick a lens on it, and drag it out to the club. With the Panasonic/Leica Summilux-DG 25mm lens, focusing for still snaps

Re: Aliasing question

2013-10-10 Thread Godfrey DiGiorgi
I have no problems getting clear hand-held shots with ASA 400 film at f/2.8, 1/4-1/8 second, EV 3 on the chart you referenced. Without IS. With my G1, I find quite a number of excellent shots, even of people moving, at light levels which, according to your chart, is ISO -1. Heck, I have some

Re: Aliasing question

2013-10-10 Thread Steve Cottrell
On 9/10/13, Godfrey DiGiorgi, discombobulated, unleashed: (Psst: My new camera is on the way to me now, although I doubt anyone on the PDML is interested to know that other than a couple of friends. However, Cotty will gush over it when I carry it to the UK next year. It is sexy. ];-) Brute --

Re: Aliasing question

2013-10-10 Thread mike wilson
On 09/10/2013, Bill anotherdrunken...@gmail.com wrote: I just ordered a K3, as well as the battery grip, 35-135 lens, flu-card and dongle from my local pusher. I think I need help. You seem to be managing quite well. Unless you mean that you need help paying - in which case, I'll see you

Re: OM-D E-M5 (was Aliasing question)

2013-10-10 Thread Eactivist
Good point. No, I mean like wait a year (or eight months or so) for a real drop and more used cameras on the market. Buy some used Canon gear until then. When it comes to cameras, I've learned to be patient. Marnie aka Doe -- The Former Pentaxian ;-) In a message dated 10/9/2013 10:37:40

Aliasing question

2013-10-09 Thread Larry Colen
It seems to me that if you had a rear illuminated sensor, with no space between the pixels, and it had no bayer filter, then aliasing/moire would not happen, because the light value would be averaged over the whole sample. It's the discontinuous aspect of what is effectively three overlayed

Re: Aliasing question

2013-10-09 Thread Godfrey DiGiorgi
Aliasing occurs regardless of how close together the cells are because the cells are discrete. This kind of aliasing is a function of discrete mathematics. G On Oct 9, 2013, at 9:08 AM, Larry Colen l...@red4est.com wrote: It seems to me that if you had a rear illuminated sensor, with no

Re: Aliasing question

2013-10-09 Thread Larry Colen
On Wed, Oct 09, 2013 at 09:53:52AM -0700, Godfrey DiGiorgi wrote: Aliasing occurs regardless of how close together the cells are because the cells are discrete. This kind of aliasing is a function of discrete mathematics. I'm afraid that I left my discrete math textbook at home, and it has

Re: Aliasing question

2013-10-09 Thread Matthew Hunt
On Wed, Oct 9, 2013 at 12:53 PM, Godfrey DiGiorgi godd...@me.com wrote: Aliasing occurs regardless of how close together the cells are because the cells are discrete. This kind of aliasing is a function of discrete mathematics. I think you're dismissing Larry's point too easily. When we

Re: Aliasing question

2013-10-09 Thread Godfrey DiGiorgi
On Oct 9, 2013, at 10:52 AM, Matthew Hunt m...@pobox.com wrote: It seems to me that if you had a rear illuminated sensor, with no space between the pixels, and it had no bayer filter, then aliasing/moire would not happen, because the light value would be averaged over the whole sample.

Re: Aliasing question

2013-10-09 Thread Postmaster
Larry Colen wrote: It seems to me that if you had a rear illuminated sensor, with no space between the pixels, and it had no bayer filter, then aliasing/moire would not happen, because the light value would be averaged over the whole sample. It's the discontinuous aspect of what is effectively

Re: Aliasing question

2013-10-09 Thread Bill
On 09/10/2013 1:00 PM, Postmaster wrote: Larry Colen wrote: It seems to me that if you had a rear illuminated sensor, with no space between the pixels, and it had no bayer filter, then aliasing/moire would not happen, because the light value would be averaged over the whole sample. It's the

Re: Aliasing question

2013-10-09 Thread Mark Roberts
Bill wrote: On 09/10/2013 1:00 PM, Postmaster wrote: Larry Colen wrote: It seems to me that if you had a rear illuminated sensor, with no space between the pixels, and it had no bayer filter, then aliasing/moire would not happen, because the light value would be averaged over the whole

Re: Aliasing question

2013-10-09 Thread Larry Colen
On Wed, Oct 09, 2013 at 01:17:06PM -0600, Bill wrote: On 09/10/2013 1:00 PM, Postmaster wrote: Larry Colen wrote: It seems to me that if you had a rear illuminated sensor, with no space between the pixels, and it had no bayer filter, then aliasing/moire would not happen, because the light

Re: Aliasing question

2013-10-09 Thread Bruce Walker
On Wed, Oct 9, 2013 at 3:17 PM, Bill anotherdrunken...@gmail.com wrote: I just ordered a K3, as well as the battery grip, 35-135 lens, flu-card and dongle from my local pusher. I think I need help. Bill, please line up a model or two to shoot in early November. I'm relying on you to report

Re: Aliasing question

2013-10-09 Thread Larry Colen
On Wed, Oct 09, 2013 at 03:00:10PM -0400, Postmaster wrote: Larry Colen wrote: It seems to me that if you had a rear illuminated sensor, with no space between the pixels, and it had no bayer filter, then aliasing/moire would not happen, because the light value would be averaged over the

Re: Aliasing question

2013-10-09 Thread Doug Franklin
On 2013-10-09 16:25, Larry Colen wrote: Actually, what I think Doug should do is paint his racecar in a bayer filter of 2mm squares, just to screw with the trackside photographers. As one of said trackside photographers, I don't think I want to give anyone else any ideas. :) -- Doug Lefty

Re: Aliasing question

2013-10-09 Thread Larry Colen
On Wed, Oct 09, 2013 at 04:53:51PM -0400, Doug Franklin wrote: On 2013-10-09 16:25, Larry Colen wrote: Actually, what I think Doug should do is paint his racecar in a bayer filter of 2mm squares, just to screw with the trackside photographers. As one of said trackside photographers, I

Re: Aliasing question

2013-10-09 Thread Doug Franklin
On 2013-10-09 17:04, Larry Colen wrote: When the halftones get shot and the results aren't so hot that's a moire. Eek! :) Woo hoo! Next week is Petit le Mans! Flagging a day or two, and supporting the flaggers and other volunteers for the rest of the event. When I'm not flagging, I'll

Re: Aliasing question

2013-10-09 Thread Matthew Hunt
On Wed, Oct 9, 2013 at 3:25 PM, Mark Roberts postmas...@robertstech.com wrote: It isn't because of the space between pixels, which has no effect on aliasing. I disagree; see the references in my email. A high pixel fill factor acts essentially as a lowpass filter, substantially reducing

Re: Aliasing question

2013-10-09 Thread Bill
On 09/10/2013 2:13 PM, Bruce Walker wrote: On Wed, Oct 9, 2013 at 3:17 PM, Bill anotherdrunken...@gmail.com wrote: I just ordered a K3, as well as the battery grip, 35-135 lens, flu-card and dongle from my local pusher. I think I need help. Bill, please line up a model or two to shoot in early

Re: Aliasing question

2013-10-09 Thread Matthew Hunt
To show the effects of pixel fill factor on aliasing, I coded up a small simulation. This 1000x1000 starting image: https://dl.dropboxusercontent.com/u/20239870/Aliasing/micro-auto-focus-test-2.png (from http://www.komar.org/faq/camera/auto-focus-test/ ) represents the image falling onto a

Re: Aliasing question

2013-10-09 Thread Larry Colen
On Wed, Oct 09, 2013 at 08:16:41PM -0400, Matthew Hunt wrote: To show the effects of pixel fill factor on aliasing, I coded up a small simulation. This 1000x1000 starting image: Awesome! https://dl.dropboxusercontent.com/u/20239870/Aliasing/micro-auto-focus-test-2.png (from

Re: Aliasing question

2013-10-09 Thread Matthew Hunt
On Wed, Oct 9, 2013 at 8:35 PM, Larry Colen l...@red4est.com wrote: It would be a lot easier to see if you could have each point of your output be 9x9 pixels, then the resulting image would be the same size as the original (which is giving me aliasing on my display BTW). Fair enough, but

Re: Aliasing question

2013-10-09 Thread Larry Colen
On Wed, Oct 09, 2013 at 08:16:41PM -0400, Matthew Hunt wrote: To show the effects of pixel fill factor on aliasing, I coded up a small simulation. This 1000x1000 starting image: I don't speak python, but to have an output array of the same size, would I want something like: def

Re: Aliasing question

2013-10-09 Thread Matthew Hunt
I'm fairly new to Python, but that looks about right. It might be possible to avoid the two innermost loops (x9, y9) by assigning directly to a slice: outbig[x*9:x*9+9, y*9:y*9+9] = value Not sure if that works. There's another shortcut you can use at the beginning: outbig =

Re: Aliasing question

2013-10-09 Thread Eactivist
You know, someone asked me the other day because I have been a computer programmer, if I had ever been a geek. I said no, not really. I think that is confirmed now. Marnie aka Doe ;-) In a message dated 10/9/2013 5:17:39 P.M. Pacific Daylight Time, m...@pobox.com writes: To show the

Re: Aliasing question

2013-10-09 Thread Godfrey DiGiorgi
Don't feel bad, Marnie. They're significantly geekier than I am, and that's saying a lot. I'd rather be geeky making photographs, however. (Psst: My new camera is on the way to me now, although I doubt anyone on the PDML is interested to know that other than a couple of friends. However, Cotty

Re: Aliasing question

2013-10-09 Thread Larry Colen
On Wed, Oct 09, 2013 at 06:49:13PM -0700, Godfrey DiGiorgi wrote: Don't feel bad, Marnie. They're significantly geekier than I am, and that's saying a lot. I'd rather be geeky making photographs, however. (Psst: My new camera is on the way to me now, although I doubt anyone on the PDML

Re: Aliasing question

2013-10-09 Thread Eactivist
Pssst. I am still seriously interested in the Olympus EM-5. BUT... going to wait until I can get it used. Marnie aka Doe :-) I don't know, Godfrey, you seem pretty geeky to me. ;-) Re camera: cool. In a message dated 10/9/2013 6:50:01 P.M. Pacific Daylight Time, godd...@me.com writes:

Re: Aliasing question

2013-10-09 Thread Godfrey DiGiorgi
Please define low light vs dim light for me. EV values would be useful as a basis of comparison. G On Oct 9, 2013, at 7:02 PM, Larry Colen l...@red4est.com wrote: ... My only complaint with u4/3 has been with their sensor performance in low light conditions. It seems as if the u4/3 sensors

Re: Aliasing question

2013-10-09 Thread Larry Colen
On Wed, Oct 09, 2013 at 08:03:42PM -0700, Godfrey DiGiorgi wrote: Please define low light vs dim light for me. EV values would be useful as a basis of comparison. I guess I'd say that low light is in the range where it is challenging to get a clear photo, hand held, even with a K-5. Looking

Re: OM-D E-M5 (was Aliasing question)

2013-10-09 Thread Aahz Maruch
On Wed, Oct 09, 2013, eactiv...@aol.com wrote: Pssst. I am still seriously interested in the Olympus EM-5. BUT... going to wait until I can get it used. keh.com currently has them for $695/LN- or $665/EX+ (I'd probably go ahead and spend the extra $30 for LN- but it really doesn't matter