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Fun with the RX-1

douglasf13

New member
The glass gets very close to the sensor. this does however not mean, just like with the sigma dp1 and dp2, that the exit pupil, in optical sense, is close to the sensor. My impression was that these lenses are build this way, close to the sensor, almost covering it, to delivers parallel rays of light to the sensor, to improve the quality. especially the Sigma sensor is, as I understand it, sensitive for this.
and is it not so that the color shift here occurs form one side to the other? In that case nothing to do with the lens, at least not on its own. and flash seems to cure it, once again suggesting it is not just the lens.
Yeah, the exit pupils of the X100, DP1, RX-1, etc. are still relatively far from the sensor, although it seems that Sony didn't optimize things as much as they could have, considering the RX-1 has a fixed lens and it is not THAT wide at 35mm. It certainly doesn't bode well for those wanting a FF NEX to use with M lenses, if Sony can't even nail the color shift thing with the RX-1.

p.s. here's a little bit of insight as to why color shift can be asymmetrical: Sony NEX-C3 first impressions - FM Forums
 

barjohn

New member
By the way, just read Lloyd Chambers first review of the RX1. His analysis of the lens performance is very positive and worth reading. He rated the lens performance as very sharp with very good micro-contrast from f2-f11 with the optimum at f4. There was virtually no field curvature measured. There is a bug in the firmware where image size changes between f16 and f22. He demonstrates his findings with sample images and toggles between images for illustration. He highly rates the bokeh.

He points out a few short comings, one of them being that the camera does not open the lens to f2 during AF or MF thus making focus less accurate than it might be if it had to focus with minimum DOF. This seems to be a problem with so many mirror-less cameras. You would think by now they would have fixed this and only actually stopped down the lens just before firing the shutter.

Another complaint he had was that if the camera is powered off or turns off for any reason it loses its focus set so if you had the camera on a tripod and had preset your focus waiting for some event and you powered off the camera to save battery life and quickly turned it on to take a shot it would not be set to your preset focus.

Another complaint was the inability to use CDAF to select a focus point on a magnified image provided by focus assist.

There were a few more minor issues he raised. Somehow he missed the issues raised by Ken Rockwell. :)
 

Shashin

Well-known member
He points out a few short comings, one of them being that the camera does not open the lens to f2 during AF or MF thus making focus less accurate than it might be if it had to focus with minimum DOF. This seems to be a problem with so many mirror-less cameras. You would think by now they would have fixed this and only actually stopped down the lens just before firing the shutter.
I believe this is a constraint of the exposure system. There is a loss of accuracy at wide apertures.

So, he did not agree with Ken. Funny thing is, neither did I...
 

barjohn

New member
Frankly, I don't understand why there would be a loss of accuracy on exposures at wide apertures versus any other aperture. It seems to me that it is a straight forward math problem to convert the value from one to another.

I didn't say he didn't agree with KR, I said he didn't mention the issues that KR raised. I don't know whether he would agree with KR or not. I know I don't.
 

Shashin

Well-known member
Frankly, I don't understand why there would be a loss of accuracy on exposures at wide apertures versus any other aperture. It seems to me that it is a straight forward math problem to convert the value from one to another.
It has to do with the cone size and shadowing on the sensor at large apertures. Since the engineer was Japanese and I wasn't, I was not able to go into much detail as I raised the same sort of questions.
 
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Vivek

Guest
Frankly, I don't understand why there would be a loss of accuracy on exposures at wide apertures versus any other aperture. It seems to me that it is a straight forward math problem to convert the value from one to another.
This is one big problem that Sony seem to have. It is best they address it and solve it. I am also not sure about their WB calculations and the limited WB range. Incandescent lighting should start with 2000K value and not 2500K. That could be the root of the problem. Nikon do much better job.
 

barjohn

New member
I suspect that there must be more to this than we understand. Most engineering organizations thoroughly dissect their competition's equipment carefully noting parameters selected and behavior and doing whatever level of reverse engineering is needed to provide a better performing competitive product. Further as the sensor supplier they know things about their sensor that companies buying and using their sensors will not know. That is why, as an engineer, this doesn't make sense. There has to be a mathematical relationship between f-stop and shutter speed and WB even if it is not a linear equation. This equation can be applied once the values for one set of values are measured and known to derive any other combination of shutter speed and aperture selected by the user. If the computation is too complex, precomputed values can be entered into tables for use.
 

Shashin

Well-known member
This equation can be applied once the values for one set of values are measured and known to derive any other combination of shutter speed and aperture selected by the user.
Which is why f/4 is used to obtain the data, but you can make exposures at f/2.
 

douglasf13

New member
He points out a few short comings, one of them being that the camera does not open the lens to f2 during AF or MF thus making focus less accurate than it might be if it had to focus with minimum DOF. This seems to be a problem with so many mirror-less cameras. You would think by now they would have fixed this and only actually stopped down the lens just before firing the shutter.
My Fuji X100 was constantly opening and closing the aperture, depending on the light conditions, and it drove me crazy. It adds to shutter lag, and it can also potentially lead to focus shift issues. If the RX-1 works like NEX, then the camera AFs at shooting aperture until the light gets low enough, and then the camera switches to staying wide open. The chattering back and forth in good light with the Fuji really annoyed me.
 

Shashin

Well-known member
He points out a few short comings, one of them being that the camera does not open the lens to f2 during AF or MF thus making focus less accurate than it might be if it had to focus with minimum DOF. This seems to be a problem with so many mirror-less cameras. You would think by now they would have fixed this and only actually stopped down the lens just before firing the shutter.

I just checked my camera. The aperture does indeed open to f/2 in AF and MF. I have no idea what he is talking about.
 

Shashin

Well-known member
Another complaint was the inability to use CDAF to select a focus point on a magnified image provided by focus assist.
Focus assist is for MF. Why would there be an AF point for MF? If you are using DMF, then the AF has finished and then the operator then adjusts focus in MF in focus assist. Lloyd is starting to sound like Ken...
 

barjohn

New member
Shashin,

You are mistaken. Set the camera to A mode, set the lens to f4, 1/2 press the shutter so the camera tries to AF on an object. Watch the iris, it does not change from the f4 setting. On any DSLR, focusing is done at the widest aperture and then the lens stops down to the selected aperture just before the shutter opens. You will see that on this camera, that it will not attempt to open the iris until you go above f8. Then it will open to the f8 position during focus and go back to the selected f stop after it finds focus.

The magnification assisted AF/MF is frequently used on other mirror less cameras. You get a magnified image and this has the effect of creating a smaller focus box that you can precisely place and you press the AEL button to obtain a locked focus. This is very handy for use on a tripod and when setting up for zone or hyperfocal focusing.
 

barjohn

New member
My Fuji X100 was constantly opening and closing the aperture, depending on the light conditions, and it drove me crazy. It adds to shutter lag, and it can also potentially lead to focus shift issues. If the RX-1 works like NEX, then the camera AFs at shooting aperture until the light gets low enough, and then the camera switches to staying wide open. The chattering back and forth in good light with the Fuji really annoyed me.
Douglas,

Yes, that is a problem with the X100. I'm not talking about having it do what the X100 does. Se my response to Shashin. On the X100 the iris was constantly changing as the light changed. You did not need to press the shutter button at all. Further it did not go to open (f2) for focusing either which made manual focusing impossible at higher f stops because the DOF was so large you could not tell where the exact focus point was located, even with a magnified image.
 

Shashin

Well-known member
Shashin,

You are mistaken. Set the camera to A mode, set the lens to f4, 1/2 press the shutter so the camera tries to AF on an object. Watch the iris, it does not change from the f4 setting. On any DSLR, focusing is done at the widest aperture and then the lens stops down to the selected aperture just before the shutter opens. You will see that on this camera, that it will not attempt to open the iris until you go above f8. Then it will open to the f8 position during focus and go back to the selected f stop after it finds focus.
Sorry John, I was reading it another way thinking it could not AF/MF at wider apertures than f/4.

But did Lloyd actually show that AF at the shooting aperture is less accurate? I have seen no evidence of it, although in low light the AF slows down at smaller apertures, but I am unsure if that is just because of illumination or DoF. I think the comparison of Phase detection in a DSLR to CD in a mirrorless is not a great comparison.

The magnification assisted AF/MF is frequently used on other mirror less cameras. You get a magnified image and this has the effect of creating a smaller focus box that you can precisely place and you press the AEL button to obtain a locked focus. This is very handy for use on a tripod and when setting up for zone or hyperfocal focusing.
The Sony function is simply for MF, hence the name MF Assist. They clearly state that. Don't fault an MF function because it works exactly like it should and does not AF. My E-P1 works just like my RX1, so it is not universal. Lloyd might like to have that, but that is not a fault. I am not even sure it is really very useful--what is so hard to use AF and then fine tune with MF Assist. It seems unnecessary to have a magnified AF. And why not praise for the RX1 way of setting up zone focus--put AF on the C button so in manual focus you can get a focus point with AF and then quickly confirm it with MF Assist and then just shoot away.

Sorry, but there comes a time when nitpicking simply becomes annoying. Ken is just making stupid comments and now Lloyd is just picking at things that are not even worth mentioning and certainly not showing that it is actually significant to the operation.
 
Ok, enough chit chat.
Here's another typical Waikiki photo.
Windy, cloudy and light showers but I've taken a vow to never complain about the weather.
Shot raw only so here is my weak attempt using Lightroom.
Enjoy.

f/8
 

retow

Member
Ok, enough chit chat.
Here's another typical Waikiki photo.
Windy, cloudy and light showers but I've taken a vow to never complain about the weather.
Shot raw only so here is my weak attempt using Lightroom.
Enjoy.

f/8
Thank you for posting great pics and using the camera for picture making:clap::clap: Whenever a new camera was being announced which pushed technical boundaries, after a first wave of enthusiastic user feedback some obsessed with finding "technical flaws" would take over and blow it up all over the www (M9, FUji X10, XPro1, Nikon 800, etc. etc.).
 
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