[stevebrot]

Does that make sense, or am I getting confused again?

You are making sense. I am going to take a break here and eat breakfast. The thread should catch up with itself by the time I have that done and get dressed and all.


Steve

[BigMackCam]

You are making sense. I am going to take a break here and eat breakfast. The thread should catch up with itself by the time I have that done and get dressed and all.

Thanks for the sanity check

Since the current aperture setting doesn't appear to represent the base exposure shot, but instead the first shot of the bracketed sequence (eg. the "-" shot for a "- 0 +" sequence), it means we need to consider this when metering our shot. If it's a three shot bracket with 1/3EV intervals in "- 0 +" order, then we need to meter our shot at -1/3EV... which is a distinctly odd way of working, IMHO

[pschlute]

It seems that if we're right about the way it's working, with "- 0 +" ordering, the camera should impose a maximum aperture setting *two* intervals down from the lens's maximum - so, f/1.8 in this instance - in order to take shots at f/1.8, f/1.6 and f/1.4.

You are assuming here that the camera will only adjust aperture to give your three bracketed exposures. That is not the case

---------- Post added 03-27-2017 at 03:55 PM ----------

This is in M-mode (see thread title and description of bug). Three steps of the e-dial should be one stop difference in aperture, not two.


Steve

In normal modes yes, but in bracket mode you are handing control of the parameters to the camera. You twist the dial three clicks for 1 stop, but the camera is making other adjustments to give you your -0.3 EV bracket. It does sound illogical I agree but perhaps this is the answer.

I knew there was a reason I dont use bracket in M mode!

[BigMackCam]

You are assuming here that the camera will only adjust aperture to give your three bracketed exposures. That is not the case

But why wouldn't I assume that, if I'm in M mode with the green button functionality set to Av Shift? Surely that suggests that bracketing should adjust the aperture and nothing else. In that instance, it should - I would think - impose a maximum aperture setting that ensures all of the bracketed shots are within the range of available apertures.

In any case, if it's adjusting more than the aperture as you suggest, why hasn't it adjusted the shutter speed or ISO in the final "+" shot of the example I gave? The "0" and "+" shots had exactly the same aperture, shutter speed and ISO setting.

As far as I'm now aware, setting green button functionality for M mode defines whether aperture and shutter speed can be adjusted by the camera (P), aperture only (Av) and shutter only (Tv), and these also affect how the bracketing exposure is controlled in the same way. Otherwise, what's the point of setting green button functionality to affect bracketing (and it clearly does affect it)?

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Last edited by BigMackCam; 03-27-2017 at 08:10 AM.

[BigMackCam]

Looking further into this...

With the bracketing order changed back to the default of "0 - +", M mode and green button set to Av Shift or disabled, the maximum aperture setting allowed is the maximum of the lens. The resulting sequence of shots on my FA50/1.4 are "0" at f/1.4, "-" at f/1.6 and "+" at f/1.4, all the same shutter speed; so the "0" and "+" shots are identical. Again, you would expect the camera to enforce a maximum aperture setting that would allow all shots in the bracketed sequence to be within the possible range of apertures.

Regarding the other issue - the odd jump in aperture settings with the aperture e-dial - the default bracketing order does indeed restore normal operation, whereas switching to "- 0 +" causes exactly the behaviour Steve described.

[stevebrot]

it means we need to consider this when metering our shot. If it's a three shot bracket with 1/3EV intervals in "- 0 +" order, then we need to meter our shot at -1/3EV... which is a distinctly odd way of working, IMHO

You are correct. One must consider the bracket order when metering in M-mode.

In normal modes yes, but in bracket mode you are handing control of the parameters to the camera. You twist the dial three clicks for 1 stop, but the camera is making other adjustments to give you your -0.3 EV bracket.

Ummm...I expect 1/3 stop per click on the aperture dial, both directions.

I suggest you spend some time with your K-1 and work through the examples in the original post. If the behavior appears consistent to you, then that is OK. I don't judge. I believe you are correct in that the aperture sequence may be emulating the bracket sequence (or something else, say perhaps the aperture portion of the program line), but that is not the "contract" the camera has with the user. That is why it is a bug, not a feature.

The broken contract rules are as follows:

• The e-dial does not consistently increment/decrement aperture in 1/3rd stop steps as per system settings
• The system does not properly bracket exposure (EV) when the set aperture is within one bracket step of the lens maximum aperture.

Steve

[Just1MoreDave]

The broken contract rules are as follows:

• The e-dial does not consistently increment/decrement aperture in 1/3rd stop steps as per system settings
• The system does not properly bracket exposure (EV) when the set aperture is within one bracket step of the lens maximum aperture.

Steve

My camera and FA 35/2 were right there so I set it up and gave it a try. My K-5 IIs does not have the first "broken contract" problem: the e-dial changes the aperture as expected. (The only time I've seen something similar was my brother's K-r, which periodically needs blasts of contact cleaner for proper e-dial function.) My camera does break the second rule - I get the same incorrect bracket set you get.

Also my K-7 works the same way as my K-5 IIs. The K-7 doesn't have any custom settings for the green button.

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Last edited by Just1MoreDave; 03-27-2017 at 10:50 AM.

[pschlute]

Just tested my K1 with DFA 24-70 2.8

Set EV steps to 1/3 stop
Disabled green button in manual
Bracketing order -/0/+

Established a scene where 1/13 f4 400 ISO gives centred exposure. Noted that each move of the Av dial changes aperture by 1/3 stop.

Further noted that changing aperture from f4 to f3.5 changes exposure meter by 1/3 stop, but moving from f3.5 to f3.2 does not change exposure meter ! Only when moving dial from f3.2 to f2.8 does the meter indication change, and indicate a 2/3 ev change in metered exposure from 3.2 to 2.8. (nb changing aperture from f4 to 5.6 is correct behaviour...eg the meter changes its reading by 1/3 steps for each 1/3 click of the Av dial.


Ok so now on to bracket.....

Turn on bracketing 1/3 stops...and immediately my camera indicates it will take the first shot at 1/13s f4.5 400 ISO. ... ie Av has changed from f4 to f4.5
Full details of the 3 exposures are:
1/13s f4.5 400 ISO (-)
1/13s f4.0 400 ISO (0)
1/13s f3.5 400 ISO (+)

While bracketing is primed each click of my Av dial changes the aperture by 1/3 stop, exactly the same if I turn off bracketing.

Now I can set my minimum aperture while bracketing is primed to only f3.2 (it is a 2.8 lens). My 3 shots show:
1/20s f3.2 ISO400 (-)
1/20s f2.8 ISO400 (0)
1/20s f2.8 ISO400 (+) !!!

But.....The third bracket although showing as taken using the same settings as the middle bracket, has been overexposed ! I can see that in both the picture and the histogram.



==================================================

Ok so now change the green button function in manual to Program Line.

No change in behaviour at all.




So wierd things:

1. moving from f3.5 to f3.2 does not change exposure meter
2. When setting aperture at widest and it appears camera cannot produce the overexposed bracket something very strange is occurring.

So perhaps it is a problem with your camera K3 that your edial does not perform correctly when bracketing is primed, as the K1 works as expected. Also changing program line settings for green button do not seem to change behaviour of the exposure in bracketing at least with the K1.

Upshot....dont use bracketing in manual !!!

[BigMackCam]

So perhaps it is a problem with your camera K3 that your edial does not perform correctly when bracketing is primed, as the K1 works as expected. Also changing program line settings for green button do not seem to change behaviour of the exposure in bracketing at least with the K1.

Upshot....dont use bracketing in manual !!!

Well, at least we know that Steve's K-3 and my K-3 are doing the same thing, so the problem is one of firmware programming rather than a fault. That's good.

As for not using bracketing in M, I'm not so sure... I'd say it's best to shoot in an order where the "0" shot is the first one - that way, the currently used aperture is the correctly exposed shot. It makes metering and adjustment a whole lot easier. Also, there's a need to remember that if the green button setting is Av Shift or "--" (disabled), we should set the aperture enough intervals down to ensure that all shots in the bracketed sequence can pick an available aperture.

I'm keen to test bracketing in Tv mode to see if that has the same bug around maximum aperture...

EDIT: Interesting... If using Tv mode and bracketing, it isn't smart enough to warn us that the current shutter speed will result in an unavailable aperture for one or more of the bracketed shots.

[pschlute]

Yes it is a weird one this. Apologies to you both for thinking that the program line was at the root of this, when it is clear from my limited testing that the the camera tries to use aperture to adjust bracketing even when program line is enabled (at least on the K1).

I wonder whether it is the fact that 1/3 bracketing is so fine that a "rounding" is taking place which complicates matters. to be honest I always have set my cameras to adjust Tv and Av and exp compensation shifts to half ev steps.With the capability of modern sensors and processing software I see no need to use 1/3 shifts. I PP all my pictures.

As for bracketing in manual mode, I was brought up on the Pentax MX and so have no problem in "bracketing" manually, and to be honest would find it more work to set the bracketing up, but I understand that if you are used to it you would prefer to work in that way.

[BigMackCam]

Yes it is a weird one this. Apologies to you both for thinking that the program line was at the root of this, when it is clear from my limited testing that the the camera tries to use aperture to adjust bracketing even when program line is enabled (at least on the K1).

I wonder whether it is the fact that 1/3 bracketing is so fine that a "rounding" is taking place which complicates matters. to be honest I always have set my cameras to adjust Tv and Av and exp compensation shifts to half ev steps.With the capability of modern sensors and processing software I see no need to use 1/3 shifts. I PP all my pictures.

As for bracketing in manual mode, I was brought up on the Pentax MX and so have no problem in "bracketing" manually, and to be honest would find it more work to set the bracketing up, but I understand that if you are used to it you would prefer to work in that way.

No apology necessary - not for me, at least It really is a weird one.

I tend to use Av mode for bracketing as a general rule, as I want to keep depth-of-field the same. Plus, I've always accepted the default bracketing order of "0 - +"... hence, I've not run into any obvious problems. It certainly seems like there's some odd stuff happening with the other bracketing options, though

[Lorrow]

Hi There! Just trying to catch up... I am working on a similar problem. I have a K3, I just updated to 1.3 Firmware. I am set 0 - +. I always use Manual mode. The E-Dial programming I adjusted was the first option on the second tab labeled M. I think it is the only e-dial setting for manual mode? Correct? I set the green button for Tv shift. Using this setting, only my shutter changes, my aperture & ISO are fixed. I am a little unsure what it is that I am supposed to do with the green button? I tried bracketing with the green button pressed and without, my results were exactly the same, exposure by exposure. Pressing the green button had no effect.

What I want to try is bracketing that will adjust both my ISO & shutter while leaving my aperture fixed. Is this even possible? I have One-Push Bracketing turned on because I am often in rapidly changing light conditions, ie Sunrise/Sunset, and my camera is much faster than I am.

[stevebrot]

I have a K3, I just updated to 1.3 Firmware. I am set 0 - +. I always use Manual mode. The E-Dial programming I adjusted was the first option on the second tab labeled M. I think it is the only e-dial setting for manual mode? Correct?

Yes

I set the green button for Tv shift.

Good

I am a little unsure what it is that I am supposed to do with the green button?

The green button will set a metered shutter speed to match your aperture. It has no special purpose for using the bracketing feature. The reason for the suggested change is to avoid the two bugs exposed in this thread.

What I want to try is bracketing that will adjust both my ISO & shutter while leaving my aperture fixed. Is this even possible?

Av mode + AE Lock + auto ISO should work, though I have never tried it. Be aware that ISO will probably not ramp for most bracket sets, which is probably a good thing.

As you may have noticed, the bracket feature works very similar to simply doing regular shots with exposure compensation. That is basically how it works.


Steve