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RedHotSly
12-26-2008, 02:24 PM
Hi,

I have a problem when I use the Aperture Priority mode and the built-in flash on my D70.

I set it to Aperture Priority mode and set the aperture to F1.8. I take a first picture without the flash: I get a picture at 1/60. I pop the flash up and take the same picture again: I get a picture at 1/15. Why is it using such a slow shutter speed when the flash is up? Of course, the end result is that all pictures I take with the flash are blurred.

I have tried the same test with another lense and with my SB-800 flash and I get the same result.

Thanks

Ben H
12-26-2008, 02:48 PM
This is a common question.

When you switch between different shooting modes, the camera does different things with the flash.

In Av mode, the flash is a fill flash only - this means, the camera will expose for the background (in low light, that means show shutter speeds) adding in a fill light from the flash. It will slow down the shutter as much as possible to bring up the ambient light.

In other modes, it assumes the flash is the main light, and exposes for that (so faster shutter speeds) but your background will be much darker.

I recommend spending some time reading your camera manual and how the flash modes change, and do some experimenting to get comfortable with flash usage.

RedHotSly
12-26-2008, 04:41 PM
Hi Ben,

Thanks for your quick answer. I did read the manual but I still can't figure out if/how to overcome this problem. I probably misunderstand the manual but there seem to be a contradiction.

(page 94) - The manual introduces the concept of "i-TTL Flash Control" and describes two modes: "i-TTL Balanced Fill-Flash" and "Standard i-TTL Flash". According to the manual, on "A" mode the D70 will use the Fill-Flash except in Spot metering. The definition for Fill-Flash is as you have described it.

(page 95) - Then on the next section, they explain flash modes. According to the manual, on "A" mode when the flash is set to "Front-curtain sync", the D70 will use a shutter speed between 1/60 and 1/500. That is clearly not what I'm experiencing.

I've tried spot metering and I get the same result.

Here is the link to the manual.
http://www.nikonusa.com/pdf/manuals/dslr/D70_en.pdf

Thanks

Ben H
12-26-2008, 06:46 PM
Its difficult to talk about a specific camera that I don't have any personal experience with - I was talking in general terms, when people get slow shutter speeds when using flash in Av mode, without understanding the difference between flash as fill and flash as main, and the fact the camera switches these modes between shooting modes.

Any camera specific behaviour I can't really offer any insight into, I'm afraid...

Travis
12-27-2008, 10:33 AM
You have to define the minimum shutter speed in the custom settings menu. The setting informs the camera as to the slowest shutter speed when using the flash in Aperture Priority (or Program) modes.

You setting is most likely set to 1/15 as the slowest speed. Change it to 1/60, or 1/30 if you are a sharp shooter. I keep mine set at 1/60 to increase usable images. When I need slow I just switch over to Manual.



EDIT: Page 162... Custom Setting #21

RedHotSly
12-27-2008, 01:22 PM
Hi Travis,

I've seen and tested setting 21. It is a somewhat good workaround. I don't know if you have noticed but the fastest value for setting 21 is 1/60. When using a zoom lens this often not enough. If I could set is to 1/125 then it would a better workaround (I don't think I'd use a flash beyond 125mm).

Nevertheless....the camera behavior is in contradiction with the manual that states that on "A" mode when the flash is set to "Front-curtain sync", the camera will use a shutter speed between 1/60 and 1/500. I'm trying to understand why it is not.


Thanks

Ben H
12-27-2008, 02:01 PM
I don't know if you have noticed but the fastest value for setting 21 is 1/60. When using a zoom lens this often not enough. If I could set is to 1/125 then it would a better workaround (I don't think I'd use a flash beyond 125mm).

The automatic modes (and semi-auto modes) are for when you don't know (or don't really care) what you want, and rely on the camera to pick an more or less appropriate setting.

If you *do* know what you want, then really the best thing to do is to go into manual, and have full control over the camera. Yes, it takes some effort to learn, but you end up being able to set up what *you* want, rather than fighting what the camera is suggesting *it* wants... they aren't always the same ;)

I tend to shoot 90% of the time in Av mode, because I want to pick the depth of field and mostly don't care about the shutter speeds (I will generally raise the ISO if I need faster shutter speeds in this mode), *except* when shooting flash where I almost always go straight into manual mode.

Then only time I shoot in Av mode with flash is when I want a slight amount of fill light - really nothing that affects the overall exposure much, so the shutter speeds will stay basically the same as with no flash at all...

RedHotSly
12-27-2008, 05:43 PM
Ben,

I get your point and I know very well how to use the M mode. If you want the long story, here it is: I'm not the only user of the camera. My wife uses it as well and knows nothing about modes. She simply grabs the camera as it is and shoots. So that night, I had installed my brand new 50mm lens and set it to A mode at f2.8 thinking it would good for the night. I know f2.8 is not and ideal setting for a party but I wanted the low DOF style to try the new lens. Anyways, she grabs the camera, turns on the SB800 and starts shooting. You can guess the result with her pictures taken at 1/15.

At this point, I must say I'm mostly trying to understand how the camera is *supposed* to work. I just hate it when I don't understand something with electronic stuff. So now I'm on the quest to find out why the camera does that.

I sent an email to Nikon so I might soon have an answer from the source…

I’ll keep you informed.

Regards,

Ben H
12-27-2008, 07:29 PM
I get your point and I know very well how to use the M mode. If you want the long story, here it is: I'm not the only user of the camera. My wife uses it as well and knows nothing about modes. She simply grabs the camera as it is and shoots. So that night, I had installed my brand new 50mm lens and set it to A mode at f2.8 thinking it would good for the night. I know f2.8 is not and ideal setting for a party but I wanted the low DOF style to try the new lens. Anyways, she grabs the camera, turns on the SB800 and starts shooting. You can guess the result with her pictures taken at 1/15.

Yeah, fair enough, understood. I'd either recommend *not* using Av mode, or setting the flash sync speed to a fixed setting, rather than the variable setting, to keep the flash as the main light source.


At this point, I must say I'm mostly trying to understand how the camera is *supposed* to work. I just hate it when I don't understand something with electronic stuff. So now I'm on the quest to find out why the camera does that.

Yes - me too. It's definitely a good idea to get to know your gear and understand how it works. I'm certainly with you on that!

Interested to hear what you find out...

bosco0633
01-10-2009, 10:56 AM
i had same issue and switched my minimum speed to 1/60 and all is good now. It use to be 1/15 as default i Believe

RedHotSly
01-12-2009, 05:45 PM
Hi,

It seems like I can't get a clear answer from Nikon. They just told me to use the minimum speed setting to workaround the problem. They won't explain why it does not select a shutter speed between 1/60 and 1/500. I'll have to live with that.

Thanks for your help

Travis
01-12-2009, 06:14 PM
I'm having a hard time understanding your beef...

If you have your min shutter speed @ 1/60 and, in AP the camera is selecting 1/60 what is the problem? The camera is selecting 1/60 to expose the ambient lighting. If you were to take your camera outside on a sunny day it might well choose 1/200 or higher to expose the ambient lighting.