Auto vs other mods - different results?

Hi all, I hope u could help cause this issue driving me crazy!
I own G5 camera, and I was trying to take the same picture with 5 different modes:
Auto, P, Tv, Av, Manual.

for some reason I got different results on all the photos!
When in fact i expected G5 to choose the same numbers for all modes.

The numbers I got:
Auto: F2.0 - 1/60
P: F2.0 - 1/10
Tv: F2.0 - 1/60 (I set Exposure to 1/60 like in Auto)
Av: F2.0 - 1/10 (I set F to be 2 like in Auto)
Manual: F2.0 - 1/60 (I chose ISO=200, and Flash 1/3, all other combinations gave very bad results)

So my question is why when I shoot on "P Mode" for example th e camera chooses Automatically F2 and 1/10 Exposure,
When for the same picture but on Auto it choses F2 1/60? How can it be?

The Tv setting came somehow the same. but then again on the Av, i got difference although everything should be the same!

On Manual I finally set f2, 1/60 but again got picture which looks different from the Auto pic with the same settings!

All the settings where set to auto when possible. (ISO, WB, etc...)The shots where taken using tripod.

I am lost please explain.

The photos can be seen here.

Thanks,
Alex.

I'm quite surprised the camera didn't use 1/60 in P mode with flash. That seems to be a common thread with many different cameras. Did you use an external flash?

You would think that as long as you had ISO on Auto, P and Auto should be the same. And if they are the same, you could set Av, Tv, and M like the other two and get exactly the same settings and results.

One thing that concerns me is that the Aperture is bumped up against the maximum size. When you took the shots, did you half-press to see if the exposure was correct? If any of the readings in the upper left of the LCD were in red, you were "out of spec".

Have you run the same tests without the flash?

Hi Alex...

I assume that since in Auto mode the camera can change all the settings, it is quite possible that it changed the ISO to stay in the 1/60 range (which is the slowest shooter the camera aims for in order to get a steady shot). Only if the f stops can go any lower or the ISO can't go higher, it will go bellow 1/60.

In P mode you set the ISO, so probably the camera needed the 1/10 to achieve equal amount of light.

In TV it gave you F 2.0 because it can't go any lower, but probably the F value was in red (at least thats how it works on the Pro1, probably the same with G5). In AV again, the camera chooses the 1/10 wich is the correct shutter speed for the ISO you set and the F2.0 value. In Manual, you can aim for anything you want, the question is what did the Light Meter said about your settings? (again, in the Pro1 you will read a -1/3 or something like that in the upper left corner)

Just an idea..., hope it helps.

Rafael Polit Jr.
Quito, Ecuador.

Thanks for the answers!
I all the modes - P, Av, Tv - the ISO speed was on Auto!

So there is no reason for the camera to change the exposure espessially on P!

Also i did half press and checked, I was always ok with the settings - no REDs no +-,
except on Manual it gave me -1/3. (also why? it should be the same as auto, i used the same exposure and aperture!)

lefturn99, I use the built in flash.
I tryied without the flash like u asked:
Auto: F4 - 1/400
P: F5 - 1/250 (ISO-Auto, no bad readings)

Again, i don't understand how with all the parameters on auto, i don;t get the same results on all the modes?

Regards, Alex.

Dear Alex,

The over-riding issue here is that you are making very rash assumptions about what you think the camera should be doing in each mode.

I suggest several things that should be tried before you even think about enabling the flash, which when used is going to complicate the issue.

1) Shoot a scene in Auto using Auto ISO and note and record ISO, Shutter and Aperture.
2) Shoot the same scene in P and note and record ISO, Shutter and Aperture.
3) Shoot the same scene in Av by setting the aperture and ISO to those recorded in (2) and note and record ISO, Shutter and Aperture.
4) Shoot the same scene in Tv by setting the shutter and ISO to those recorded in (2) and note and record ISO, Shutter and Aperture.
5) Shoot the same scene in M by setting the shutter and the aperture and the ISO settings to that recorded in (2) and note and record ISO, Shutter and Aperture.

Compare the results of all 5 shots - they should be the same. Think about the results and the setups for each step. You should now begin to understand that in Av you set the aperture and the shutter should be controlled by the light meter. Conversely, in Tv mode you set the shutter and the aperture should be set by the light meter. In P mode both the aperture and shutter will be set by the light meter, and it is difficult to predict what they will be, but they "should" result in the same exposure. In Manual mode you set everything, and the settings that you make should be consistent with what the camera told you in P mode.

At any point where your results are not what they should be, come back and let's hash over that step again.

Before you start this series of experiments, you should carefully choose your exposure sensing mode to be "Evaluative", and you should be shooting the same scene for each of the 5 shots.

Once you have fully understood how the modes are supposed to work, you can venture into use of the flash, which is another thing altogether.

Bob, I did exactly what u said. if u look on the first post i wrote. the only differnce i used flash, but than on my second post i tryied without flash too.

I perfectly understand how the modes work and the meaning of Av and Tv. and thats why i choses the apperture or exposure to be the same as in auto mode. but lets simpify the discussion lets concentrait only on
Auto and P mode:

• NO FLASH,
  
• SAME SCENE
  
• TRIPODE USED (to prevent shaking and shifting of points of evaluation. )
  
• EVALUATIVE LIGHT METERING SET.
  
• AWB SET.
  
• THE ISO IS ON AUTO IN BOTH CASES! (I hope it will rule out the ISO questions once and for all.)

Dear Alex,

Please check your Exposure Correction - I think it is set to something other than zero.
Turn the camera on and put it in Program (P) mode. You cannot make this check in Auto mode.
Press the omni control where it shows [+/-] to turn on Error Correction. I think you will find that it is not set to zero.

Another place to look is to look at the EXIF data for the pictures. There is a parameter called Exposure Bias. That should be zero if the Error Correction is set to zero.

Please try again - my G5 gives me the same settings when in P and Auto.
Thanks,

Hi Alex,

I know how frustrating this things can be, and how anoying it is to read everyone asking what one has already checked or discarded or whatever the case may be, but these questions are necesary to clarify what comes to mind to the people trying to help, and to get deeper into the real problem.

That said, in your second example, 1/400 at f 4.0 is almost the same exposure reading as 1/250 at f5.0, almost... not trully the same but very near, and also, that is a much better scenario to analyze since the camera can choose both higher and lower shuter speeds and higher and lower f stop settings.

Just to go deeper into the "anoying" questions:

first: is your scene in a light controlled situation? That is, indoor with artificial lighting and consistent color temperature and etc. or is it a situation where a window or some kind of uncontrolled factor can be an issue? (an outdoor test will truly involve uncontrolled factors that can explain the differences)

second: In Auto Mode there is really absolutely no control over any setting but the size of the image, even the ISO cannot be really set to Auto, but it is in Auto nonetheless, whatever you do (I understand that the Auto ISO in P should therefore yield the same results, so I agree: the problem is not there! ). But the camera will "remember" settings like the ones pointed by Bob: if you have chosen Exposure Compensation, it will change the final result... judging for your readings, the ND filter is probably not on, but its worth checking.

third (and the most important): Check the evaluation method used in the P mode... im not sure which is the one the Auto mode uses, but im guessing Evaluative Metering is the one used... the evaluation method will truly change the readings depending on the center subject and global lighting of the scene.

Can you post these two images to judge how different or similar they are? Im wondering: are 1/400 f4.0 and 1/250 f5.0 completely different or merely not exactly the same? (differences can reside in different WB if the situations are changing even in the smallest of measures, for instance something as simple as your place behind the camera can cast different shadows that can misslead the WB evaluation)

Rafa Polit (jr.)

Hi again!
RafaPolit, Robert_Lay,
Thanks for help i found the mistake (but only for outdoors). It was my fault sorry
I didn;t notice that the flash in PMode was not on AUTO, so it probably fired and i didn;t noticed.
So now WITHOUT using the flash i get same results!

But the problem remained when i go indoors and use the flash.
don;t confuse between AUTO_MODE and AUTO_FLASH in the discussion below:

I put the FLASH on AUTO_FLASH this time and i see the results different between the AUTO_MODE and P Mode.
But i found the source of the problem so we can narrow it pretty much to P mode only, it should be easy now.
The problem is that on P mode the camera gives me the SAME exposure reading whethere i set FLASH ON, or OFF, or AUTO_FLASH !
I always get 1/25 - F2 for my scene. Camera doesn;t compensate when using the flash in P mode
The pics can be seen here.
http://community.websh​ots.com/album/48327156​2YaSGed

Any ideas why the camera ignores the flash?

cause that is the cause of the problem, the camera ignores the flash in P mode, but DOES NOT ignore the flash in AUTO_MODE
So the camera DOES compensate when flash is ON in the AUTO_MODE.

The (+-) Flash is on Zero in the Func menu.

Thanks Again,
Alex.

P.S. Again if u can check it on ur camera and tell me that it works fine for u that the problem is me again (or my camera).

Dear Alex,

I now have the two pictures downloaded from your web site and am working on the problem. Please be patient. I will be back to you within the hour.

Thanks,

Dear Alex,
I looked at your two pictures on the Web site. It would be better if you could save your pictures and post them using ordinary methods, because we need to see the EXIF data, and the EXIF data is not embedded in your pictures. We need to be able to independently verify what your camera is doing on each shot.

The picture WITH FLASH ON is slightly brighter (very little difference) than WITH FLASH OFF. It is also slightly warmer in tone. The differences between the two pictures is hardly significant enough to notice unless you have the two pictures side-by-side for comparison.

My guess is that you are expecting the flash to have more effect than it does. If you have a much DARKER scene to start with, then the flash will make a very noticeable difference. However, in your scene, the ambient light is enough that the camera CAN give proper exposure without flash. Therefore, when the flash does fire, the sensor cuts the flash off very quickly - so the flash contributes almost nothing.
So, in my opinion, you would have to start your indoor experiments with a much darker scene in order to realize any major contribution with the flash.

I don't think that the camera is ignoring the flash in either mode. I think that if you put the flash into ON mode, it will always fire, but its sensor shuts it off almost immediately when it sees that there is enough light. If the flash is in AUTO mode, it may not fire at all if the ambient light is adequate. Again, we must have the EXIF data in each image in order to verify the camera's actual behavior. If you are saving the pictures using Save for the Web, then that may be why you are losing the EXIF data. I don't know what program you are using to process your images before posting to the Web site.

In my opinion, the problem is not with you and also not with the camera. The problem is that the scene is bright enough already that the flash is not making a significant contribution. There are ways in which you can demonstrate that the flash does exactly what it is supposed to do, but it is almost impossible to get the flash to contribute significantly when the scene is already bright enough that the camera can get a good exposure without the flash.

Remember that the internal rule that the camera uses to control the flash is that it shuts the flash down as soon as the integrated scene brightness is at the correct level.
I don't think you will ever see the flash completely dominate the picture unless you turn off the room lights.

Also, remember that you did not really complete the experiments. You should complete all the steps in the NO FLASH experiment to be sure that you are getting the correct behaviour for Av and Tv modes and that you understand them. Such tests are very helpful in gaining a better appreciation of the separate functions of the light meter and the aperture and shutter functions in each mode.

Hi Robert,
the website indeed removed all the exif info from the pictures,
any idea where else can i post the pics, so the exif info will remain?

Also I will try to answer all ur other questions ASAP.

Regards,
Alex.

Dear Alex,

The EXIF data was NOT removed by the Web Site - It was removed by "Save for Web" in Photoshop.

Hi Robert, sorry for delay with the answer, couldn;t do it earlier.
I tryied the test with a very dark scene, and it confirmed my worries, the P mode is behaving very strange.
I got again the same exposure readings for all the FLASH variants (AUTO, ON, OFF) and it was
1/1 - F2

The flash on AUTO didn't fire at all actually, although the scene is VERY dark and could not be seen without flash. so the camera doesn't read the scene correctly in P mode.

Unfortunately i can't post photos with EXIF data, I don';t use any program to post them to the web, i use a webshoots site script that uploads my photos to it, and it removes the EXIF data, as well as renames the file.
I found that i can post the photos here.
but only two of them.
That's not a problem as the AUTO_FLASH and FLASH_OFF photos are EXACTLY the same inlcuding EXIF data.

HOSTED PHOTO
please log in to view hosted photos in full size.

HOSTED PHOTO
please log in to view hosted photos in full size.

Dear Alex,

I have saved your two pictures above and your message.

I will study your message and the pictures and reply as soon as possible.
Please be patient, I will post a reply as soon as possible.