The Basics - Sensitivity/Shutter Speed/F stop

[Puffer Fish]

In the old days of 35mm, everyone knew that you controlled your film speed by what film you bought, the F stops were on the outside of the lens, and the shutter speed was set on the camera. Today, they are all mixed together, usually in some combination that comes out of the "AUTO" setting.

Over this holiday weekend, will see if I can go thru each of these, show their effect and provide some basic recommendations.

Aquagirl - this one is for you...

I'm doing this, because many of today's camera's default to setting that produce less than great results. A great example of this is the new Fuji F50... great camera, with resolution better than many DSLR's being used, but if you turn it on auto, you will get grainy, poor quality images. And if you go to the other settings, you need to know what they do.

I'll start with ISO and it's effect on picture quality... then the effect of shutter speed adjustment and finally F stop setting. To save server space, will do two images to show the difference for each one.

It would surprize most people, but a perfectly exposed G9 or F50 image, can have better image quality than a D80 or D200..but your chances of getting that image are around 1 in 200 with the point and shoot, and 85% or so with the DSLR's. Would like to see those odds go to at least 50/50.

[Silverlode]

Originally Posted by Puffer Fish

It would surprize most people, but a perfectly exposed G9 or F50 image, can have better image quality than a D80 or D200..but your chances of getting that image are around 1 in 200 with the point and shoot, and 85% or so with the DSLR's. Would like to see those odds go to at least 50/50.

The 1 in 200 point and shoot, is that on manual setting or the 'awful' (I agree with you actually) Auto setting.
Has the 'lag' in point and shoot improve? As in I'd used a G5 and it drove me nuts with the lag between each shot. The DSLR's a bliss in this area. I'd tried the Ixus recently and there's still a lag time between each shot, but I am not sure if the technology has improved but Canon may not have applied it to their lower model camera. What about the F50? Does it have this 'problem'?

[Puffer Fish]

Originally Posted by Silverlode

The 1 in 200 point and shoot, is that on manual setting or the 'awful' (I agree with you actually) Auto setting.
Has the 'lag' in point and shoot improve? As in I'd used a G5 and it drove me nuts with the lag between each shot. The DSLR's a bliss in this area. I'd tried the Ixus recently and there's still a lag time between each shot, but I am not sure if the technology has improved but Canon may not have applied it to their lower model camera. What about the F50? Does it have this 'problem'?

I am being nice, if you use "auto", then it will be zero.

Lag is less, but still a bit of an issue, but timing and such are latter subjects.

[frankc420]

I'm awaiting your posts...

[Puffer Fish]

Originally Posted by frankc420

I'm awaiting your posts...

Sorry, but will not be until tonight... have to take pictures to show things.

[gibson1525]

me too, let's get this started

[Puffer Fish]

Originally Posted by gibson1525

me too, let's get this started

I would like to keep this simple, but also show what is really going on, so people can judge for themselves. Tonight I will do:

1. ISO's effect on image quality (real world).

2. F Stop effect on how thing look (there are two aspects to this)

3. Shutter speed - what is too slow, and how to know from an image.

I will also see if I can under and over expose images and show what "adjustments" due to the image (not good, by the way).

[Cheddarchick]

Yippee!!! Thank you Puffer!!!!

[quasimoto]

Oh man, just when I am thinking about buying a camera for some UW photos you go and do this. I know my head is going to start to spin.

[Puffer Fish]

Ok.. I have taken two images, from roughly the same distance, enlarged roughly the same (If you check, I actually made the 1600 ISO a bit better, so there was no issue)

Keep in mind that this is an enlargement of a section of a picture... the original is very large.

ISO 100 -




I took this, at the edge of resolution, so it would be easy to compare.

Now the same image, in ISO 1600 -




I hope everyone can see the difference.. and in auto, this camera might actually choose 1600.

Notice the blotchy appearance in the second image... it is "Noise".

I cleaned up the images a bit, and while there is no major difference, one gets this:





Obviously, between 100 and 1600, the image varies in quality.

So, if you want the best pictures, shoot in the lowest practical ISO...