SDQ Viewfinder and Live View

[dr.noise]

Something I didn't quite get from the reviews:

1. The EVF is low-reslotion and laggy so it only for framing

2. Given that readout is taken from the same sensor, the LCD must be low-resolution and laggy too?

3. So there is no way to magnify the view and focus looking at 1:1 image pixels (like I do with legacy lenses on Olympus)?

I planned to get SDQ mainly for using with legacy lenses. But now I'm not sure.

Focus Peaking is not an option for me. It is not very informative and it does not achieve really critical focus.

 

[dr.noise]

Something strange happened. I typed a numbered list but it disappeared from the post while everything else was posted. I edited the original post so be sure you read it (again)

 

[TClair]

1) The EVF has lower resolution than newer cameras but it has not been an issue for me.

2) The LCD is excellent in my opinion.

3) The image can be magnified for critical focus in either the EVF or LCD by pressing the OK button (center of directional controller) or it can be assigned to another button, like the AF button. This is an excellent way to achieve perfect focus using either EVF or the LCD. Just as a note the lens must be in manual focus mode or a manual lens attached for this to work.

 

[dr.noise]

3) The image can be magnified for critical focus in either the EVF or LCD by pressing the OK button (center of directional controller) or it can be assigned to another button, like the AF button.

Yes, but

1. Does the magnification allow actual (1:1) pixel peeping?

2. Does it refresh fast enough to not produce blur from camera shake?

 

[PCummins]

Something I didn't quite get from the reviews:

1. The EVF is low-reslotion and laggy so it only for framing

Actually it's pretty good resolution, minimal lag. I'd estimate it's able to hit at least 50 Hz refresh, if not 60 Hz judging by some of the flickering/rolling shutter effect with overhead lights here in Australia (usually due to a fixed 60 Hz refresh assumption).

2. Given that readout is taken from the same sensor, the LCD must be low-resolution and laggy too?

No that's actually excellent, if anything the EVF tends to be a bit brighter than what you'd expect to normally see while the LCD is more accurate. Sigma definitely improved it with the DPM's over the SD15/SD1 LCD which was too low resolution to use. If you have used any of the DPM/DPQ you would experience the same on the SDQ. It seems some people prefer OVF for no lag or purist reasons but in my experience it's been fine since the DPM.

(Having said that, some way to colour correct the EVF/LCD would be a good addition for the SDQ as it's a bit difficult when the brightness is a bit out of sync with what you would normally see, so you would need to compensate for this).

3. So there is no way to magnify the view and focus looking at 1:1 image pixels (like I do with legacy lenses on Olympus)?

You probably wouldn't want to - as TClair said you can assign a button to enable manual focus zoom up to 8.0x when taking photos. You can do this with AF focus as well by pressing your assigned button while in focus lock as well to confirm focus (though it gets a bit tricky to do this while handheld).

I planned to get SDQ mainly for using with legacy lenses. But now I'm not sure.

Best to rent one for a while if possible to try it out first, or try it out in the store.

 

[Kendall Helmstetter Gelner]

3) The image can be magnified for critical focus in either the EVF or LCD by pressing the OK button (center of directional controller) or it can be assigned to another button, like the AF button.

Yes, but

1. Does the magnification allow actual (1:1) pixel peeping?I

I am not sure if it's 1:1 but it's quite a lot of zoom. Why do you need exactly 1:1?

2. Does it refresh fast enough to not produce blur from camera shake?

I can focus manually hand-holding the 50-100 f/1.8 at 100mm where the exposure time would be 13 seconds at ISO 100...

There is no blur from camera movement, if anything it's more of a "wobble" as movement causes the image to shift at slightly different rates. But not much. The focus peaking also works when zoomed. But I can definitely see well enough to focus precisely.

 

[gregscamera]

Off-topic, but since we are talking about customization: is it possible to assign the AF to a different button and separate it from shutter?

I just started out with bbf on my Sony and it feels way more natural to me than then regular setup.

 

[TClair]

Yes I have it set up for back button focus. The rear AF button does the focus then the shutter only does the exposure release. Very handy for most subjects.

 

[gregscamera]

Yes I have it set up for back button focus. The rear AF button does the focus then the shutter only does the exposure release. Very handy for most subjects.

Excellent, thank you. That is good news. BBF is very handy, in particular on a camera with slow focus. The DP Merrills apparently don't support this feature, unfortunately.

 

[dr.noise]

Best to rent one for a while if possible to try it out first, or try it out in the store.

Or wait for someone disappointed reselling it

 

[dr.noise]

I am not sure if it's 1:1 but it's quite a lot of zoom. Why do you need exactly 1:1?

Maybe I don't need exactly 1:1 but since I used it in other cameras I feel more comfortable with it.

I tested quite a lot of legacy lenses and will be doing it further.

I noticed that even the slightest focus shift affects how precise the focus is. Also there are issues like slight CA or asymmetric (decentrized optic elements?) halos around sharp objects (such as single hair) that can be stronger or weaker again depending on the small focus shifts. I.e. you can sacrifice some sharpness to improve the halos.

So basically when I replay image in camera and zoom in it (that's usually 1:1 pixel zoom) I expect to see the same image as it was during the shoot.

 

[rf-design]

Something I didn't quite get from the reviews:

1. The EVF is low-reslotion and laggy so it only for framing

2. Given that readout is taken from the same sensor, the LCD must be low-resolution and laggy too?

3. So there is no way to magnify the view and focus looking at 1:1 image pixels (like I do with legacy lenses on Olympus)?

I planned to get SDQ mainly for using with legacy lenses. But now I'm not sure.

Focus Peaking is not an option for me. It is not very informative and it does not achieve really critical focus.

I test the SDQ from a private seller and today at the Photokina and the Viewfinder is one major difference to SDM.

First the extension from the back and overview of the viewfinder is the best which I have seen until now. Not as good as the Nikon Higheyepoint 30 years but a big step for users wearing glasses.

Focus peaking is not accurate enough w/o 8x zoom. If the peaking vanish you can already see the misfocus blur on the low resolution viewfinder. The screen resolution of the viewfinder is similar to my Nex-6 but the image resolution is about a half. If the magnifier 8x is active the focus peaking is adequate for the 1.4/50mm at F1.4.

The lag is there and limit to static situation but a 1-2s AF is anyway nothing for any moving thing.

There is one very big drawback for low light composing. At about 3-4EV, I guess the display in the viewfinder stops adapting the brightness. So around 0EV or below you will see nothing than possible streetlights. Situation similar to an optical viewfinder w/o liveview.

The next point is that AF is also limited to EV above about 4. I am shure that the SDM could focus below to that light level.

 

[Capndan3]

I felt the same way (low resolution/laggy EVF... felt is was "framing quality only" as well) so was a bit disappointed in my first outing with a SDQ - the EVF location was also a bit awkward for me being "left-eye dominant"... I have a 30 day return privilege so thinking about going to a DP1Q (I'm primarily a landscape/scenics shooter) with the LVF-01 magnifier loupe instead (anyone have any experience with this combo?). I was also not sure how I was going to add wide-angle coverage - best option seemed to be the 10-20 Sigma zoom, esp. since it's $200 off right now, but the size of it plus the SDQ may have been a bit much... Otherwise, the SDQ kit (w/30mm f1.4 lens) is a bargain, the DP1Q at $699 is about right as well (plus the LVF-01 loupe at $230, but that can be used on additional DP's should I wish to expand the focal length coverage up or down...)

 

[Tom Schum]

I am not sure if it's 1:1 but it's quite a lot of zoom. Why do you need exactly 1:1?

Maybe I don't need exactly 1:1 but since I used it in other cameras I feel more comfortable with it.

I tested quite a lot of legacy lenses and will be doing it further.

I noticed that even the slightest focus shift affects how precise the focus is. Also there are issues like slight CA or asymmetric (decentrized optic elements?) halos around sharp objects (such as single hair) that can be stronger or weaker again depending on the small focus shifts. I.e. you can sacrifice some sharpness to improve the halos.

So basically when I replay image in camera and zoom in it (that's usually 1:1 pixel zoom) I expect to see the same image as it was during the shoot.

Focus magnification according to SD Quattro manual page 63: "Normally the magnification ratio is x8.0, and it is possible to change to x4.0"

If you are using Sigma electronic lenses, they are always going to operate wide open, manual focus or not, and then they close down to your selected aperture (or the camera's selected aperture) only for the exposure.

So, if there is any focus shift relative to aperture, you will never see it when manually focusing. You will see it only after you have shot the image and review it.

This is a problem with the SD Q: it lacks the capability to simply set the shooting aperture manually and then have the lens actually go to that aperture at all times, so you can focus without error. This problem could be corrected with a firmware update, but we might never see such an update. Another term we might use here is "depth-of-field preview" and the SD Quattro lacks this function.

So, if you want to nail the focus on this camera you have to use an adapted fully manual lens not available from Sigma. These might be Zeiss or Samyang, but will have to be mounted on the camera with some sort of adapter.

Yes this bothers me quite a bit. I like to have perfect focus, same as you.

I do have a 24-105mm Art lens and it autofocuses pretty well on the camera. So for now, I'm relatively satisfied.

 

[dr.noise]

Focus magnification according to SD Quattro manual page 63: "Normally the magnification ratio is x8.0, and it is possible to change to x4.0"

Magnification itself does not provide information how "true" are the pixels. For example, 1:1 pixel scale corresponds to 14x magnification in Olympus camera, but the same 1:1 pixel scale may as well correspond to 8x magnification in Sigma camera.

So, if there is any focus shift relative to aperture, you will never see it when manually focusing. You will see it only after you have shot the image and review it.

Sorry, I was a bit unclear. By focus shift I mean physical shift of the focus ring. Luckily I haven't seen any focus shift (aperture-related) in my lenses, except one.

This is a problem with the SD Q: it lacks the capability to simply set the shooting aperture manually and then have the lens actually go to that aperture at all times, so you can focus without error.

Yes, that would be great to have.

 

[rf-design]

I am not sure if it's 1:1 but it's quite a lot of zoom. Why do you need exactly 1:1?

Maybe I don't need exactly 1:1 but since I used it in other cameras I feel more comfortable with it.

I tested quite a lot of legacy lenses and will be doing it further.

I noticed that even the slightest focus shift affects how precise the focus is. Also there are issues like slight CA or asymmetric (decentrized optic elements?) halos around sharp objects (such as single hair) that can be stronger or weaker again depending on the small focus shifts. I.e. you can sacrifice some sharpness to improve the halos.

So basically when I replay image in camera and zoom in it (that's usually 1:1 pixel zoom) I expect to see the same image as it was during the shoot.

Focus magnification according to SD Quattro manual page 63: "Normally the magnification ratio is x8.0, and it is possible to change to x4.0"

Sorry Tom,

to bring back this rather old thread. I did not fully understand if the "focus shift" is a doubt or a clearly observed optical property of some lenses. I do not consider mechanical problems of interaction the apture motor with the focusing and moving lens group.

I remember old drawings explaining some primary lens errors. One of explaination show that the outer rays focus more in front of the image plane. That is called spherical abberation. It is very intuitive to asscociate the optical focus shift to this textbook theory. This hold true for only one lens but a multilens design would correct this error to some extend. If you focus for the central part of the apture the geometrical errors of the lens would go to zero for a single wavelenght. Only diffraction will up and does contribute to any "focus shift".

If the lens design overcorrect the spherical abberation the "focus shift" could have a opposite direction. So the claimed effect depend stronly on the lens design but guessing that the lens designer try to correct the spherical abberation for all wavelenghts. So in extreme case the "focus shift" could depend on wavelength.

If the lens design is an extreme "focus shifter" the outer rays would intersect before or behind the image plane. Anyway the total result of the outer rays and the center rays would be blurrred image. So if you focus for best sharpness you will place the image plane somewhere between the intersection point of the outer rays and the center rays. Your argument is now that if you focus at target apture you avoid this shift and get a slightly better sharpness.

Before the age of electronic focusing nearly all cameras system try to use maximum apture for focusing. With the SDQ and the MC-11 adapter the situation got mixed.

SDQ + GV or nonGV lens focus an maximum apture opening (not checked by me, proposed by you)

NEX6 + MC-11 + nonGV lens focus on maximum apture opening

NEX6 + MC-11 + GV lens focus on target apture

NEX6 + Sigma DN lens focus on target apture

NEX6 + Native Sony lens focus on target apture

If Sigma decide to operate the AF and manual focus of the SDQ on open apture and Sony is doing this different there should be a technical argument. One could be that Sony have enough SNR margin to focus in low light and prefer that the user could observe the effect of the apture. Sigma have issues anyway with focusing below about 4EV and compromize user feedback of the apture effect.

To your argument the focus shift is the more compromizing situation.

I would be interessted if actual lens test doing refocusing at target apture or if the effect is so small that it would not change the test result. If focus stacking for the lens test is used and the maximum sharpness is numerical extracted the "focus shift" should be seen if the stacking number differ. I doubt that the effect is noticeable because the resolution difference between maximum apture and the apture where the resolution is at max is typical not more than factor two. So a point light source is spread by a factor two in the image plane. Assuming that wider spread at the maximum apture mainly orign in the outer rays the center rays at the resolution peaking apture contribute only to the half spread circle.

Now my argument: If the lens design have a "focus shift" these center rays are out of focus and contribute to a point light source image spread similar to the outer rays. So the total resolution does not increase by closing apture. This is a contradiction to the observed increase of the resolution with closing apture for most high apture fixed focal lenght lenses. The very good low apture zoom lens show typical only decrease of resolution with apture at there smallest focal length. So they are getting diffraction limited from the start and do not show resolution peaking.

Now my doubts: If a lens show resolution peaking it will not have significant, or you can observe significant, focus shift. If a lens is not far from diffraction limit it also have no focus shift.

If you are using Sigma electronic lenses, they are always going to operate wide open, manual focus or not, and then they close down to your selected aperture (or the camera's selected aperture) only for the exposure.

So, if there is any focus shift relative to aperture, you will never see it when manually focusing. You will see it only after you have shot the image and review it.

This is a problem with the SD Q: it lacks the capability to simply set the shooting aperture manually and then have the lens actually go to that aperture at all times, so you can focus without error. This problem could be corrected with a firmware update, but we might never see such an update. Another term we might use here is "depth-of-field preview" and the SD Quattro lacks this function.

So, if you want to nail the focus on this camera you have to use an adapted fully manual lens not available from Sigma. These might be Zeiss or Samyang, but will have to be mounted on the camera with some sort of adapter.

With the above arguments I doubt that the resolution difference from a small amount of focus shift is a good argument to go through a difficult adaption journey. Another argument is that you can use focus stacking in manual mode with SA-lenses also with your expected focus shift.

I have two excellent Samyang lenses (2.0/12mm, 1.4/21mm) designed for mirrorless APS-C instead for FF. I could compare them to the 1.8/18-35mm on a 16MP but from sighting images they are not better than the Sigma 1.8/18-35mm. They are much more compact, with a Sony body nearly compact as the Panasonic LX100. That is there strength.

Yes this bothers me quite a bit. I like to have perfect focus, same as you.

I do have a 24-105mm Art lens and it autofocuses pretty well on the camera. So for now, I'm relatively satisfied.

--
Tom Schum
Celebrate mediocrity (in moderation)

Reiner

 

[D Cox]

Yes I have it set up for back button focus. The rear AF button does the focus then the shutter only does the exposure release. Very handy for most subjects.

Excellent, thank you. That is good news. BBF is very handy, in particular on a camera with slow focus. The DP Merrills apparently don't support this feature, unfortunately.

They do. It is a menu option for the top button.

 

[Tom Schum]

I noticed that even the slightest focus shift affects how precise the focus is. Also there are issues like slight CA or asymmetric (decentrized optic elements?) halos around sharp objects (such as single hair) that can be stronger or weaker again depending on the small focus shifts. I.e. you can sacrifice some sharpness to improve the halos.

Sorry Tom,

to bring back this rather old thread. I did not fully understand if the "focus shift" is a doubt or a clearly observed optical property of some lenses. I do not consider mechanical problems of interaction the apture motor with the focusing and moving lens group.

Your argument is now that if you focus at target apture you avoid this shift and get a slightly better sharpness.

To your argument the focus shift is the more compromizing situation.

I would be interessted if actual lens test doing refocusing at target apture or if the effect is so small that it would not change the test result.

Now my argument: If the lens design have a "focus shift" these center rays are out of focus and contribute to a point light source image spread similar to the outer rays. So the total resolution does not increase by closing apture. This is a contradiction to the observed increase of the resolution with closing apture for most high apture fixed focal lenght lenses. The very good low apture zoom lens show typical only decrease of resolution with apture at there smallest focal length. So they are getting diffraction limited from the start and do not show resolution peaking.

Another argument is that you can use focus stacking in manual mode with SA-lenses also with your expected focus shift.

Reiner

I don't have the technical expertise to address many points in your post, and would like to mention that dr.noise seems to have much better knowledge and experience in my opinion.

Somebody, maybe in this same thread, reported focus shift evidence in even Sigma's better Art lenses. This bothers me.

Your theory about aberration being a cause makes perfect sense to me. This is a good reason to set a lens to the shooting aperture and then focus it if you want to get as close to perfection as possible.

I have seen small amounts of focus shift using a Samyang 85mm F1.4 X-mount lens on my Fuji X-E1 camera. That is, if I focus at F1.4, then stop down and shoot, I get a slightly blurrier shot than if I focus at the shooting aperture (say, f5.6). So, when I use this lens and camera I always focus at shooting aperture, which I set manually. If I could adapt it to run on the sd Quattro I would, but it is made for Fuji X-mount so adapting it is out of the question. Maybe I could get another one in Pentax K mount...

My big point is that if a lens has focus shift such as this, I will never see it if I am using the sd Q, until I inspect the images after they are shot. This is because I can't shoot Sigma electronic lenses at the shooting aperture. I'm working on getting a modern lens onto the camera that is fully manual, likely to be a Pentax K mount lens modified by removal of the aperture lever. Then I can use a modern lens to focus at shooting aperture on the sd Quattro. If Sigma made any manual lenses in SA mount this chore would be easy.

When I had a SD1 I had to focus-bracket to get the best shot. This was so frustrating that I got rid of the camera. I hoped to avoid this with my sd Quattro and with a simple firmware change this would be the case.

Actual scientific type testing such as you propose seems to me a very good idea, and I'm sure Sigma already knows quite well what the exact numbers are. This might be part of the math that goes into the factory setting of the focus parameters in the Art lenses, data that we can fiddle with using a USB dock. My older Sigma lenses don't have this capability and I can't get good focus out of them except manually at maximum aperture if I am lucky, but these statements of mine are purely anecdotal, not the sort of scientific evidence that would be best.

 

[rf-design]

I noticed that even the slightest focus shift affects how precise the focus is. Also there are issues like slight CA or asymmetric (decentrized optic elements?) halos around sharp objects (such as single hair) that can be stronger or weaker again depending on the small focus shifts. I.e. you can sacrifice some sharpness to improve the halos.

Sorry Tom,

to bring back this rather old thread. I did not fully understand if the "focus shift" is a doubt or a clearly observed optical property of some lenses. I do not consider mechanical problems of interaction the apture motor with the focusing and moving lens group.

Your argument is now that if you focus at target apture you avoid this shift and get a slightly better sharpness.

To your argument the focus shift is the more compromizing situation.

I would be interessted if actual lens test doing refocusing at target apture or if the effect is so small that it would not change the test result.

Now my argument: If the lens design have a "focus shift" these center rays are out of focus and contribute to a point light source image spread similar to the outer rays. So the total resolution does not increase by closing apture. This is a contradiction to the observed increase of the resolution with closing apture for most high apture fixed focal lenght lenses. The very good low apture zoom lens show typical only decrease of resolution with apture at there smallest focal length. So they are getting diffraction limited from the start and do not show resolution peaking.

Another argument is that you can use focus stacking in manual mode with SA-lenses also with your expected focus shift.

Reiner

I don't have the technical expertise to address many points in your post, and would like to mention that dr.noise seems to have much better knowledge and experience in my opinion.

Somebody, maybe in this same thread, reported focus shift evidence in even Sigma's better Art lenses. This bothers me.

Your theory about aberration being a cause makes perfect sense to me. This is a good reason to set a lens to the shooting aperture and then focus it if you want to get as close to perfection as possible.

I have seen small amounts of focus shift using a Samyang 85mm F1.4 X-mount lens on my Fuji X-E1 camera. That is, if I focus at F1.4, then stop down and shoot, I get a slightly blurrier shot than if I focus at the shooting aperture (say, f5.6). So, when I use this lens and camera I always focus at shooting aperture, which I set manually. If I could adapt it to run on the sd Quattro I would, but it is made for Fuji X-mount so adapting it is out of the question. Maybe I could get another one in Pentax K mount...

Thank's Tom,

that is a new information for me. That seem to me as a design flaw of this lens. It could be acceptable to the design targets of a complete manual lens. That means that the cam does not have any apture control. But as you explain most user would focus open apture and then loose resolution. It does not need scientific test if you can observe this by careful examination. If that is until now an underestimated lens issue it could be because the arrival of the target apture fosusing methods. Before the lens where possible designed for minimum focus shift. Now the picture change.

My big point is that if a lens has focus shift such as this, I will never see it if I am using the sd Q, until I inspect the images after they are shot. This is because I can't shoot Sigma electronic lenses at the shooting aperture. I'm working on getting a modern lens onto the camera that is fully manual, likely to be a Pentax K mount lens modified by removal of the aperture lever. Then I can use a modern lens to focus at shooting aperture on the sd Quattro. If Sigma made any manual lenses in SA mount this chore would be easy.

I have token to reps from Samyang and Tokina about there technical issues of integrating on sensor AF capabilities into there lens lines at the Photokina. Both reported that moving a heavy lens group within milliseconds for the high step rate of these new AF algorithms is a major burden for the lens manufacture. Samyang had difficulities doing the AF 1.4/50mm FE lens and Tokina going MF.

When I had a SD1 I had to focus-bracket to get the best shot. This was so frustrating that I got rid of the camera. I hoped to avoid this with my sd Quattro and with a simple firmware change this would be the case.

I have the same issues with the SD1M but get used to work with or around. SDQ promise but did not impress me.

Actual scientific type testing such as you propose seems to me a very good idea, and I'm sure Sigma already knows quite well what the exact numbers are. This might be part of the math that goes into the factory setting of the focus parameters in the Art lenses, data that we can fiddle with using a USB dock. My older Sigma lenses don't have this capability and I can't get good focus out of them except manually at maximum aperture if I am lucky, but these statements of mine are purely anecdotal, not the sort of scientific evidence that would be best.

True, with the newer fast lens group moving electromechnalical solutions they could change the focus at exposure time. I have doubts that they doing this beside it is possible.

--
Tom Schum
Every day a new image.

Reiner

 

[Tom Schum]

Before the lens where possible designed for minimum focus shift. Now the picture change.

True, with the newer fast lens group moving electromechnalical solutions they could change the focus at exposure time. I have doubts that they doing this beside it is possible.

However, this does not mean that the focusing algorithm sets the lens at perfect focus at maximum aperture. Likely it sets the lens at some small offset so when the aperture closes down focus is perfect (as estimated by the USB dock data, maybe?). Meanwhile, the user does not see the small difference in the viewfinder. No need to move focus groups fast.

Pixel counts have gone very high, making visible even the smallest deviations from peak lens performance. If a Sigma electronic lens is designed for minimum focus shift, there is no way to know if there has actually been a shift until after the sd Quattro shot is taken.

Basically I don't even bother to use anything on my sd Quattro except my only global vision lens, a 24-105 F4 Art. Works great. Someday, I'll get a manual lens mounted...

--
Tom Schum
Every day a new image.