is this correct

[boxer82003]

sorry im a bit mixed up does a higher apature # like 20 create less DOF

where an apature of 4 have a larger DOF meaning more of the image will be in focus

here an example of what seems to be the story of my photography life

most of my pictures look similar to this

http://members.shaw.ca/samplephoto/test/poor.jpg

this one is a bit better but most look like the first

http://members.shaw.ca/samplephoto/test/better.jpg

what am i doing wrong

[DocFrankenstein]

ummm... not using a tripod... or a timer?

[DReb-MO]

what are you going for here? If it's to stop action you have the shutter open too long. If the motion of the water is what you are after looks like you might need a tripod or an IS lens. It could be that it's too windy to get what you want on this day but that's a bit less likely. I am sure those with other ideas will chime in.

[Scottes]

An aperture of f/4 will have less depth of field than an aperture of f/22.

One key point when hand-holding is to use a shutter about equal to the focal length. So with a 50mm lens, use a shutter speed of 1/50th. (If you're using a 10D or D-Rebel multiply that by 1.6, so about 1/80th second.) Set set the camera to Tv mode and set the correct shutter, and check the aperture. If the aperture isn't small enough ("larger" f/ number, like f/22) then either increase the ISO or - much better bet - use a tripod.

For shots like this you'll really want a tripod. You could always try resting the camera on a rock or something, but pressing the shutter will shake the camera so use Timer mode so you're not touching the camera when the shutter actuates.

It's *highly* recommended to use a tripod for shots like this. It will do a world of good.

PS: The second picture is quite good.

[JZaun]

boxer82003

The bigger the f# the deeper the dof.
What confuses people is the bigger the f# the smaller the opening .:? F1 wide open f22 very small opening. Nothing in pic one was in focus so the answer to that is in the other post....Camera movement! shutter speed too slow or just not holding the cam still enough.

JZ

[boxer82003]

the second picture is what i was going for its just that most of my pics look like the first one blurry outta of focus i wanted the water to look like it does

[GPR1]

What you have is a shutter speed issue. You are trying to hold the camera when the shutter speed is too slow. As Scottes said, good technique will allow to hold any lens at a shutter speed of 1/focal length, or 1/50 second for a 50mm lens, 1/100 for 100mm, etc. That technique does require practice, however. As others said, a tripod in these low light situations is almost a must. (My guess is your sharper picture was taken around f4 because that allowed you a faster shutter speed, and the fuzzy picture was taken at f22 and a very slow shutter speed).

Keep working at it, and consider investing in a tripod.

Greg

[boxer82003]

ok thanks guys so what your saying from what i understand f22 will allow more dof but will require a slower shutter speed thus causing the out of focus look like pic #1 (unless im using my tripod) and would require more light (so this technique may require higher iso)

where a lower f stop like f4 would be less dof (more background blur only subject in focus ) yet better in low light and will give me a higher shutter speed (and may be able to get away with a lower iso)

am i getting this right or am i in left field

[Scottes]

You're perfectly correct Boxer.

Just to nit-pick, the problem in #1 is camera shake, not lack of DoF. f/22 gives maximum DoF, but since the shutter was so slow the camera shook during the long exposure time.

[FlipsidE]

That all sounds right to me.

Just remember the aperture is meastured as 1/x rather than just x. The higher the number, the smaller the opening. f/4 = 1/4 where f/22 = 1/22.

Taking DoF out of the discussion, I like to think of it like cable/dsl versus dial-up. To set up the scene, let's say two different people were downloading the same file from the same site at the same location...one on cable/dsl, the other on dial-up. The dial-up connection is a narrow-band connection (less bandwidth) and the cable/dsl connection is a broadband connectoin (more bandwidth). The dial-up connection must stay open longer to receive the same file because the pipe used to get the data is smaller than the broadband connection.

Think of the dial-up connection as a high number f-stop and the broadband connection as a low number f-stop. The wider the pipe, the faster the needed light can get in resulting in a faster shutter speed. The narrower the pipe, the slower the needed light can get in resulting in a slower shutter speed. The downside of a wider pipe is that allows less time for other things to come into focus before the shutter closes. The downside of a narrow pipe is that it requires the shutter to be open for longer meaning the camera must stay very still for longer periods of time.

FlipsidE

[elbirth]

FlipsidE, that's a PERFECT analogy for shutter speed vs aperture size! :)

If I didn't already understand how it worked, that would have made everything chrystal clear!

[Jon]

The other thing to bear in mind is that the 1/focal length setting for hand-holdable shutter speed is primarily for 35 mm users. With a digital camera, you need to consider the lens focal length and crop factor. So a 200 mm lens on a DReb should generally be handheld at 1/320 sec. or faster for relatively camera-motion-free pictures.

[tofuboy]

ok thanks guys so what your saying from what i understand f22 will allow more dof but will require a slower shutter speed thus causing the out of focus look like pic #1 (unless im using my tripod) and would require more light (so this technique may require higher iso)

where a lower f stop like f4 would be less dof (more background blur only subject in focus ) yet better in low light and will give me a higher shutter speed (and may be able to get away with a lower iso)

am i getting this right or am i in left field

Keep in mind there are 3 main components that contribute to the brightness of an image. Shutter Speed, Aperture, ISO. So changing 1 of them, means you have to alter the others accordingly

Say at ISO 100, 1/100s and f/4.0 is the correct settings for the desired exposure... but you want more DOF, so you go from f/4.0 to f/5.6 (one full stop of change). Going from f/4.0 to f/5.6 decreased the amount of light entering the camera by half, so to compensate you need to adjust the shutter speed OR the ISO. That would mean either
ISO 200, 1/100 s and f/5.6 OR ISO 100, 1/50 s and f/5.6

So in your case, if you wanted the largest DOF, you would use f/22... but you can still use ISO 100 to keep the noise levels down, but you will have to slow the shutter speed down. Or you could adjust the ISO up a notch or two, and drop the shutter speed a notch or two to get the right exposure.

Learn how these 3 things work together and you're on your way to more control over how your photos turn out.

[Deckyon]

Jon, that is not entirely correct. Crop factor is not Zoom. It only has to do with the Field of View. A 200mm lens is STILL 200mm on the rebel/10d/20d. BUT it is missing the outter portion of the scene. It is cropped.

Lets say a 35mm picture is printed at 5x7. Lay down a piece of 4x6 paper in the middle of the 5x7 paper. Now, cut off the fringes of the 5x7 to match the 4x6. That is cropping. Same thing with the difference in the chips. The chip sees the scene at the same size, just a small (narrower) Field of View.

So, it is still 1/200 on the 200mm lens on the Rebel/10D/20D.

If I am wrong, then the visiting instructor from the Nikon School is wrong, because this is roughly how he explained it.

[tommykjensen]

Ok which is it?

So with a 50mm lens, use a shutter speed of 1/50th. (If you're using a 10D or D-Rebel multiply that by 1.6, so about 1/80th second.)

So, it is still 1/200 on the 200mm lens on the Rebel/10D/20D.

[Deckyon]

When you CROP, you are not ZOOMING. Crop factor does not make the image LARGER, it only makes the FIELD OF VIEW smaller.

[Jon]

When you CROP, you are not ZOOMING. Crop factor does not make the image LARGER, it only makes the FIELD OF VIEW smaller.

But when you crop, you have to magnify the resultant image more for a given final image size, so the camera shakes are also magnified more. Crop factor refers to the image size on sensor. But it's the final output image size that we look at. And I am not saying that crop factor=focal length multiplier. That's a whole different argument. But if you take a picture with a full-frame sensor (or 35 mm film) at 1/f.l., then crop it so you're using a 22.5 x 15 mm area, and blow that up to 8x10, the results will be less acceptable (from camera motion) than if you'd printed the full frame.

Think of it this way. Your camera shake is (arbitrary number) 1 mm/sec. You shoot at 1/60 sec. with a 50 mm. lens (1/f.l.), so shake, linearly, is 1/60 mm. That gives you a right triangle of 1/60 mm base and 50 mm height representing the shake. If you're shooting full frame, that's out of a right triangle of 21.5 mm base (43.5 mm diagonal for a 24x36 mm frame) and 50 mm. height. If you're looking at a D30, D60, DR, 10D, 20D, the equivalent triangle is 13.5 mm base and 50 mm ht. Scale those triangles out to provide 8x10 in. coverage and you'll find that the 1/60 mm on the negative/sensor has been magnified along with everything else. But it's been magnified more on the camera with the 1.6x crop factor.

[aam1234]

Jon's answer is so complicated it must be right :D (I didn't understand a word).

[Jon]

OK - You shake the camera 1 mm per second (actually difference in motion between the lens nodal point and the film plane) - that's just your jitters. At 1/60 sec. that makes 1/60 mm blur on the negative/sensor. Now blow that up to an 8x10 print of the full frame (either "full frame" 24x36 mm, or 1.6x crop 15x22.5 mm). The blur from a "full frame" neg. will be magnified about 8x (24 mm is about an inch). From a 1.6x crop neg., blur will be magnified about 13x on the same 8x10 print size. I hope that's better.

[aam1234]

Oh I believed you the 1st time. Thanks for the help.

[Jon]

Thank you for keeping me "honest", or at least lucid!

[boxer82003]

my god will this ever get easy its gonna take me an hour to take a photo as i replay all the setting in my head

[Jon]

my god will this ever get easy its gonna take me an hour to take a photo as i replay all the setting in my head

That's what the DoF Preview button's for! That and rules of thumb like 1/fl (as amended) and "sunny 16") will help you keep things moving. But taking "an hour" as you sort out what effect you want is actually a good thing, as it teaches you to look at the subject.