# HDR....???



## PNA (Feb 1, 2007)

A thought just occurred to me regarding HDR......

If auto ISO is set, and you bracket 3 shots resetting only the aperture, will the 3 shots be exposed differently to use for merge HDR????? Doesn't the ISO change to accommodate the resetting of the aperture and the 3 shots all expose the same???? :er: 

I haven't tried it yet, but tomorrow is comming.......


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## Maxx RS4 (Feb 1, 2007)

I believe you dont change the aperture but just the shutter speed. that shouldnt affect your iso.


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## PNA (Feb 1, 2007)

Maxx RS4 said:


> I believe you dont change the aperture but just the shutter speed. that shouldnt affect your iso.


 
Are you suggesting using shutter priority and adjust only the shutter speed?

I've been using aperture priority.


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## JTHphoto (Feb 1, 2007)

bracketing is intentionally underexposing and overexposing by a specified number of stops, regardless of whether you change your aperture, shutter speed, or ISO.  In your case, the ISO shouldn't change, that's my understanding anyway...


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## Arch (Feb 2, 2007)

you should only change shutter speed when doing HDR... changing the aperture changes the DOF.... not good for merging images  ... changing iso would be too noisy for my liking too.


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## fmw (Feb 2, 2007)

Archangel is right as long as you are not at infinity focus.  Use manual mode and under and overexpose with the shutter speed.  Remember, you will use a tripod so the shutter speed doesn't matter as long as the subject isn't moving and moving subjects are not a good candidate for this technique.


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## PNA (Feb 2, 2007)

Archangel said:


> you should only change shutter speed when doing HDR... changing the aperture changes the DOF.... not good for merging images  ... changing iso would be too noisy for my liking too.


 
A point very well taken....I never considered that a change in DOF occurred when adjusting the aperture when bracketing.

On the D70....Can I then use shutter priority instead of aperture priority??? That way the shutter speed changes when bracketing instead of the aperture??? 

Using manual is always an option.

Thanks....and fmw also.


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## Digital Matt (Feb 2, 2007)

Shutter priority maintains a set shutter speed and varies the aperture.  That's the mode NOT to use.  Aperture priority would be the mode that maintains the aperture.  You would have to use exposure compensation, or auto bracketing to get the different exposures.  To me, this is silly and requires reading the manual way too much.  The best way to do it is to use manual mode and bracket manually.  A simple change of the shutter speed is all that's needed.


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## Arch (Feb 2, 2007)

edit: matt beat me to it but.....

yea you should always use manual for attempting HDR..... if for example you wanted to try a HDR made up of three images.... one would be exposed correctly, one would be overexposed slightly and the other underexposed.

If you tried to do this is in a priority mode, the camera would try and compensate for the under/over exposures.

Some HDRs may consist of 7-8 exposures... the last of which would be very dark, so you can only really achieve this in manual mode.


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## PNA (Feb 2, 2007)

OK, manual for bracketing!!! understood.

What about *auto* ISO.....any effects on bracketing exposures?

I plan to try all configuration today and report finding......

Thanks, Guys.


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## Digital Matt (Feb 2, 2007)

Manual implies that you set everything.  I don't know if auto ISO would even work in manual mode.  If so, it would be stupid.  Use a tripod, and always use the lowest ISO, to get the most noise free picture.  As stated, this technique is not for moving subjects, so the duration of the exposure is not an issue.


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## shingfan (Feb 2, 2007)

say you are using tripod to get different exposures.......i would image between different exposures...there might be a slight shift in the composition if you are pressing the button manual.....or is it better to use wireless control?....or a slight shift in composition is acceptable?


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## Digital Matt (Feb 2, 2007)

If the exposures aren't identical, they won't line up.  If you don't have a remote, use the self timer.  Wait a second after you change the shutter speed until the camera stops shaking.  I use a remote and mirror lockup.


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## PNA (Feb 2, 2007)

Matt....that was the point of my question , ISO should be _manual/fixed_ and not auto, with a tripod and wireless remote.

Hummmm.....mirror lockup also??? for shake reduction???? interesting!

This setup is seems to be primarily for studio use....outdoors, it must be completely calm.

Thanks


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## Digital Matt (Feb 2, 2007)

I don't know anything about auto ISO, because my camera does not have it, and even if it did, I would not use it.  I like to tell the camera what to do.  I use mirror lockup always, when shooting static subjects.  If I turn on the self timer and mirror lock, I get a 2 second delay after locking the mirror, before the shutter.


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## shingfan (Feb 2, 2007)

acsonpg said:


> Matt....that was the point of my question , ISO should be _manual/fixed_ and not auto, with a tripod and wireless remote.
> 
> Hummmm.....mirror lockup also??? for shake reduction???? interesting!
> 
> ...


 
mirror lockup for blocking the light going into viewfinder


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## fmw (Feb 2, 2007)

shingfan said:


> mirror lockup for blocking the light going into viewfinder


 
No, mirror lock up to prevent the moving mirror from causing camera shake.


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## shingfan (Feb 2, 2007)

fmw said:


> No, mirror lock up to prevent the moving mirror from causing camera shake.


 
ok now...this is a different term than i read ....can you explain what mirror lockup is with more details?.....

i always thought mirror lockup is just putting the mirror lock on the viewfinder...or that is called the viewfinder lock?.....anyways....can teach me how this is done....thanks


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## Digital Matt (Feb 2, 2007)

In an SLR, the mirror reflects light into a pentaprism, and through the viewfinder to your eye as a corrected image.  When you press the shutter release, the mirror has to swing up out of the way so the light has a direct path to the film plane.  The shutter opens and the light is recorded.  With mirror lock, you compose the photo, and then manually raise the mirror prior to exposure.  This prevents the vibration caused from the mirror swinging out of the way during exposure.  In most cameras, with mirror lock enabled, pressing the shutter release once raises the mirror, and pressing it a second time fires the shutter.  The mirror returns down to its normal position so you can compose and meter the next shot.  Some manual cameras have a lever that rotates the mirror out of the way.  You have to manually bring the mirror back down after exposure.  This is handy if you are bracketing because once composed, you don't need the mirror until you are done bracketing exposures.


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## shingfan (Feb 2, 2007)

how about shutter shake?...is that significant?


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## PNA (Feb 2, 2007)

I may be doing something wrong.......once the mirror is locked up, the shutter can not be activated with the shutter button. I need to turn the camera off the mirror falls into place, turn the camera on and take a photo.

Bummer......

P.S.  I turned off the _auto ISO._


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## Digital Matt (Feb 2, 2007)

It sounds like you might be using the "sensor cleaning" aspect of your camera, which does lock the mirror up, but only for cleaning.  Maybe your camera does not offer mirror lock.  You'll have to read your manual.

Shingfan, there's nothing you can do about shake caused from the shutter.  The shutter has to open and close.  The D70 and a few other cameras use an electronic shutter, where power is turned on and off to the sensor to control exposure.  This would obviously not suffer from any shake.  Shutter shake is pretty insignificant compared to mirror shake.


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## shingfan (Feb 2, 2007)

Digital Matt said:


> It sounds like you might be using the "sensor cleaning" aspect of your camera, which does lock the mirror up, but only for cleaning. Maybe your camera does not offer mirror lock. You'll have to read your manual.
> 
> Shingfan, there's nothing you can do about shake caused from the shutter. The shutter has to open and close. The D70 and a few other cameras use an electronic shutter, where power is turned on and off to the sensor to control exposure. This would obviously not suffer from any shake. Shutter shake is pretty insignificant compared to mirror shake.


 
i see....i'm going to try when i get home......hopefully i can figure it out from the on camera menu....


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## Digital Matt (Feb 2, 2007)

Why is everyone allergic to their camera manual?


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## PNA (Feb 2, 2007)

Just called Nikon.....Matt, you're right, the mirror lockup is for cleaning purposes only. There is no mirror lock on the D70 except for "blub" and that's for extended timed shots.

edit:   I could't find anything in the ****'n manual on mirror lock only mirror lockup!

Your bowing student,
Paul


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## shingfan (Feb 2, 2007)

Digital Matt said:


> Why is everyone allergic to their camera manual?


 
ppl are allergic to "READ"


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