What am I doing wrong???

Bigvin

Bigvin

Suspended / Banned
Messages
616
Edit My Images
No
Another really stupid beginners question with probably a really obvious answer.

I'm just starting out with photography and i've bought myself a Nikon D5000 with the two kit lenses (18-55 and Tamron 70-300) I've bought a beginners magazine that explains a bit about aperture, exposure, ISO and the rest.

They've got some simple exercises to go through to teach you the effects of altering different settings.

I'm having a problem with one of the exercises on aperture settings.

The exercise says to just take the same photo several times with different aperture settings and then look at the differences between the DOF.

I've done this a number of times and the only effect I get is that the picture goes from really dark to really bright as I would expect using a smaller aperture.

Can anyone point me in the right direction?

Cheers
 
Try focusing on a subject close to you with something in the background, a portrait for instance. Then do the excersize again :-)
 
Are you in AV mode?.
AV mode should alter the shutter speed automatically when you alter the aperture.
If you are in AV mode then what you are describing should not happen.
 
Try increasing the iso or using a longer exposure for higher F stops

md ?
 
Sounds like the shutter speed is staying constant as you change the aperture... P or AV mode is your friend for this exercise...
 
Best way I can think to help you see the affects would be to take a photo of the edge of something side on. (eg. Looking down the edge of a table from one end to the other) Focussing on one end

With an aperture of say F2.8 you will notice that the end of the table you DIDNT focus on will be out of focus

But with an aperture of say F11 you will notice most of the table on both ends will be more in focus.
 
Easiest way is to set your camera to "A" which is aperture priority mode, this means you set the aperture and the camera sets the shutter speed, this means your image will be correctly exposed. So the image will not go from overexposed to underexposed and you will see the difference the aperture makes to DOF.
 
Paul Male said:
Try focusing on a subject close to you with something in the background, a portrait for instance. Then do the excersize again :-)
Click to expand...

Thanks for the reply.

Unfortunately I get the same problem again.

Although I am just in the house and the distance between the object and background is only about 6 feet.

How much distance should I try to get between them?

Cheers
 
Do you know I've started this 4 times already :lol:. Exposure is a function of Aperture, shutter speed and film speed (ISO rating); assume speed is constant (ISO 100 or 200 for e.g) so don't change it; then the exposure is a function of aperture and shutter speed. First off, on aperature, as the number goes down the iris size gets bigger, e.g f4.0 go down to to f2.8 and the iris size gets bigger, and more light can enter the lens; on shutter speed, if you go from 1/60 to 1/30 the shutter stays open longer and more light can enter the lens. So thats sorted then, low aperture number and slow shutter speed number, its sorted. you might think so, thats the problem, slow shutter speeds and any action is blurred, simple enough, but low aperature numbers whats the problem?; DOF thats the problem. DOF (Depth Of Field) is that range of the picture which is "in focus" in front of the the subject and that beyond the the subject.
Two typical photos, a portrait and a picture of a castle in a glen. In a portrait you want a picture of the person in focus, any thing in front or behind may be a distraction, so to make it of no interest, so it is best to make it blurred.
With a low Aperature 1.8 or 2.8 that which is in focus is not much in front or beyond the subject (Its said to have a shallow DOF, say for a 1.8 aperture at 50mm, half a yard in front and three quarters beyond, which gives you an acceptable range of 3 to 4 feet, although a tack sharp range of something less. So for a portrait a shallow DOF is preferred and this will also generally mean a fast shutter speed; now with a landscape (the castle in the glen) the foreground and the ground beyond the castle is of interest as it gives the castle perspective and how the castle fits in with the surroundings, so the foreground and background is important; to achieve this you may need a amall aperature of f16 or f22 a wide depth, so to get the same amount of light through the lens you would need a slower shutter speed. Big aperture (low number) fast shutter, small aperture (large number) slow shutter for the same amount of light. So back to your question :- You were asked to change the aperture setting and study the DOF. So set the camera for AV or apaeture priority (as you change the aperture the shutter speed will change automatically to allow the same amount of light throrough the lens). For the same same photo as you change the aperture (say from f22 to f8 on a bright day) you should notice the shutter speed quicken, say from 1 second to perhaps 1/15 second, (tripod needed)) but if is look closely that which your eye says is in focus will change as the f number comes down; the bits in front and beyond will be come narrower, but the overall brightness of the picture should remain about the same.
 
As the others have said, it sounds like you've got your camera in Manual mode (M).

What you're seeing is the effect changing the aperture only has on exposure.
 
Craig F -
Are you in AV mode?.
AV mode should alter the shutter speed automatically when you alter the aperture.
If you are in AV mode then what you are describing should not happen.
Click to expand...

That could well happen if he is selecting an aperture say F22 and the ISO and Shutter speed cannot compensate the difference then you will get an underexposed photograph, likewise if he takes a photo in pure sunlight with an aperture of F2.8, even at ISO100 and Shutter 1/8000 it might not be enough and would overexpose
 
CraigF said:
Are you in AV mode?.
AV mode should alter the shutter speed automatically when you alter the aperture.
If you are in AV mode then what you are describing should not happen.
Click to expand...


Yeah I'm in Av mode.

Cheers
 
Davec223 said:
Easiest way is to set your camera to "A" which is aperture priority mode, this means you set the aperture and the camera sets the shutter speed, this means your image will be correctly exposed. So the image will not go from overexposed to underexposed and you will see the difference the aperture makes to DOF.
Click to expand...

What he said.. lol " Why can i never explain thing simple like that"

md
 
Example;

Left image F1.4
Right Image F16

dof-comparison.jpg


NOT MY IMAGE!
 
Bigvin said:
Another really stupid beginners question with probably a really obvious answer.

I'm just starting out with photography and i've bought myself a Nikon D5000 with the two kit lenses (18-55 and Tamron 70-300) I've bought a beginners magazine that explains a bit about aperture, exposure, ISO and the rest.

They've got some simple exercises to go through to teach you the effects of altering different settings.

I'm having a problem with one of the exercises on aperture settings.

The exercise says to just take the same photo several times with different aperture settings and then look at the differences between the DOF.

I've done this a number of times and the only effect I get is that the picture goes from really dark to really bright as I would expect using a smaller aperture.

Can anyone point me in the right direction?

Cheers
Click to expand...

Edit: Ooops! Crossed post with everybody. I guess you've got the message now :D

Choose subject that runs from near to far, like a fence or wall, and stand at an angle to it. Use the 18-55 lens at about 30mm and focus on an area about four feet away. Lock the focus by switching it to manual.

Set the camera on Av so that it will automatically compensate for the change in the aperture by adjusting the shutter speed. Shoot a series of pictures from the lowest f/number to the highest, and see how the area in front of the focus point, and behind it, becomes sharper as the f/number gets higher.

NB If the shutter speed gets longer than about 1/30sec when shooting with the highest f/numbers, raise the ISO or the images will be blurred with camera-shake and you'll not be able to see the depth of field changing.
 
Wow I can't believe how fast the replies are coming in.:thumbs:

I've just gone through all of the posts and can confirm that I'm definately in A mode on the camera and not M mode.

I'll try and get a picture looking sideways on to something.

Cheers
 
Hope my advice helps you :P
And dont be suprised at how quick the replies are coming in, were a friendly forum.

And I forgot to mention WELCOME!
And another note, there's no such thing as a stupid question so if you're having problems just do a search of the forum first, if you dont find what you're looking for make a thread :D
 
Cheers J4mie P.

Just tried taking a shot of my guitar and I noticed that the shutter speed doesn't adjust when I adjust the aperture.

Any ideas?
 
IF your in A mode then the camera should adjust the shutter speed as mentioned above
Could you post two pics to show the issue?
 
Go out in the garden tomorrow (as long as its not raining!) and take an image focusing on a subject in the garden using the different aperture settings.:)
 
When you adjust your aperutre on A mode, the shutter speed will still stay the same I believe untill you half press the shutter once again for it to reevalute the metering for the scene.

Not 100% sure on this though
 
Just took 2 photos and they were both the same except one was light and the other was dark???

Tried holding the shutter half way down and the shutter speed just stays the same.
 
Where the shutter speeds different or the same?
 
OK just found something else.

The shutter speed changes when the built in flash is closed, but stays at 1/60 when the flash is open, no matter what aperture settings I put in.

Is this right?

Cheers
 
What shutter speed is showing in the viewfinder?

Just one thought, are you using a flash?

If you are this could also be causing your problem, to much light when the lens is wide open, not enough light when the lens is stopped down.
 
The maximum flash sync is usually 1/200
so usually it will change up or down within that range, seems strange that it's not changing.
But on the other note, if you are using flash you will notice at higher shutter speeds (such as 1/200) there will be less ambient light in your photo. But at the other end at say 1/50 there will be more ambient light in your photograph that could explain your darker and lighter photographs.
 
Ok typing my response when you posted, nikon onboard flash sync at 1/60th of a second, that is a constant, unless you use an external flash sb600/800/900. The on board flash will not give enough light when lens is stopped down. Remember that for every stop you shut down the lens you need twice as much light. So from f4 to f5.6 you need twice as much light and when you stop down to f8 from f5.6 you need twice as much light again which means 4 times as much light as you needed at f4. Hope this helps a little.
 
J4MIE_P said:
The maximum flash sync is usually 1/200
so usually it will change up or down within that range, seems strange that it's not changing.
But on the other note, if you are using flash you will notice at higher shutter speeds (such as 1/200) there will be less ambient light in your photo. But at the other end at say 1/50 there will be more ambient light in your photograph that could explain your darker and lighter photographs.
Click to expand...

Tried taking two pics, one at 1/200 and one at 1/50. There seems to be no difference to me!!

The shutter speeds with the flash on stay the same, so I'm guessing that's why the images are lighter and darker. I don't know if that's normal or not, so i'll take some pictures tomorrow in daylight and see what happens with them.

I'll try and host them somewhere so you can see them and get an idea of what I mean.

I'm off to bed now cos i'm up for work in a couple of hours.

Once again many thanks to everyone who has helped.
 
Davec223 said:
Ok typing my response when you posted, nikon onboard flash sync at 1/60th of a second, that is a constant, unless you use an external flash sb600/800/900. The on board flash will not give enough light when lens is stopped down. Remember that for every stop you shut down the lens you need twice as much light. So from f4 to f5.6 you need twice as much light and when you stop down to f8 from f5.6 you need twice as much light again which means 4 times as much light as you needed at f4. Hope this helps a little.
Click to expand...

Thanks for this, I didn't realise about the increase in light needed when you step down.

Maybe I should go back and read more of the manual. :$

Many thanks for the info.
 
Not sure what camera you have got but does the 'A' setting by any chance mean 'Auto'?

OOps .. just re-read and see you have a D5000!
 
Bigvin said:
Thanks for this, I didn't realise about the increase in light needed when you step down.

Maybe I should go back and read more of the manual. :$

Many thanks for the info.
Click to expand...

I should have said the light increase is when the shutter speed stays the same.
 
OK I went out into the garden today and took a couple of pictures with different aperture values.

Pic 1.
1/1.3 F5.6
3.jpg



Pic 2.
4 F9
2.jpg





Pic 3.
13 F14
1.jpg




I had to put the camera into auto to get a visible picture. The settings the camera used were 1/40 F5.6.


Have I set something up wrong?

Cheers
 
Ok, another question, have you mistakenly dialed in some + exposure compensation, by going to the auto mode the camera ignores the compensation which could be why you are getting washed out read overexposed in "a" mode while getting correctly exposed image in auto mode
 
OK, just trying to find out about the exposure settinigs.

Would it be worth me just resetting the custom settings?
 
According to the EXIF, you have +4.67 exposure compensation dialled in. This is why you are overexposing your pics. Turn Exposure compensation down to 0 and you should be good.
 
Heres the exif from pic1.

Orientation of image: 1
File change date and time: 2010:03:25 18:22:01
Image input equipment manufacturer: NIKON CORPORATION
Image input equipment model: NIKON D5000
Software used: PaintShop Photo Pro 13.00
Exposure time: 13
F number: 14
Exposure program: 3
ISO speed rating: 200
Exposure bias: 4.66667
Maximum lens aperture: 5
Metering mode: 5
Light source: 0
Flash: 0
Lens focal length: 48
Sensing method: 2
Custom rendered: 0
Exposure mode: 0
White balance: 0
Digital zoom ratio: 1
Focal length in 35 mm film: 72
Scene capture type: 0
Gain control: 0
Contrast: 0
Saturation: 0
Sharpness: 0
Subject distance range: 0

not sure exposure bias should be 4.66667 but could be wrong.

damn to late.
 
Davec223 said:
Ok, another question, have you mistakenly dialed in some + exposure compensation, by going to the auto mode the camera ignores the compensation which could be why you are getting washed out read overexposed in "a" mode while getting correctly exposed image in auto mode
Click to expand...


Looks like that was it. :thumbs:

I have no idea how that got altered. Not even sure what it's for. :lol:

Many thanks.
 
jomike said:
According to the EXIF, you have +4.67 exposure compensation dialled in. This is why you are overexposing your pics. Turn Exposure compensation down to 0 and you should be good.
Click to expand...

That sorted it mate. :thumbs:
 
essexguy78 said:
Heres the exif from pic1.

Orientation of image: 1
File change date and time: 2010:03:25 18:22:01
Image input equipment manufacturer: NIKON CORPORATION
Image input equipment model: NIKON D5000
Software used: PaintShop Photo Pro 13.00
Exposure time: 13
F number: 14
Exposure program: 3
ISO speed rating: 200
Exposure bias: 4.66667
Maximum lens aperture: 5
Metering mode: 5
Light source: 0
Flash: 0
Lens focal length: 48
Sensing method: 2
Custom rendered: 0
Exposure mode: 0
White balance: 0
Digital zoom ratio: 1
Focal length in 35 mm film: 72
Scene capture type: 0
Gain control: 0
Contrast: 0
Saturation: 0
Sharpness: 0
Subject distance range: 0

not sure exposure bias should be 4.66667 but could be wrong.

damn to late.
Click to expand...

Bit scary how you get that info from the pic.

Gonna have to do a search to find out how to do that.
 
You must log in or register to reply here.
Back
Top