Depth of field and focusing test

[Bristol Pete]

Any opinions?

Starting out and jumping straight into the manual settings of my 350D to expedite my ability. Taken in RAW and converted to JPEG, resized to fit forums using Microsoft picture resize....

Please with the focusing and depth here....its a good start..I think?

Thanks,

Pete.

 

[richard plumb]

what apertures? I'm assuming the first shot was deliberately on the mag not the model.

the second shot is nice but personally I think the background is still too much in focus.

 

[Bristol Pete]

what apertures?

F3.5 but its all new to me. I concur with the second comment too....

What ISO do you reckon for a potrait shot/test? The camera shoots portrait in 400 in auto mode...is this about right for now?

Thanks,

Pete.

 

[barongreenback]

I'd always shoot in ISO 100 as a general rule, unless light conditions dictate otherwise. I'm not sure what you're intending to do here - if you are using flash then you can get away with a wide aperture and a relatively fast shutter speed although your background may be underexposed.

Whatever aperture you use, if your subject is very close to the background, it won't go much out of focus (assuming you're using the kit lens)

 

[Bristol Pete]

There is so much to get your head around isnt there!!!

This was a test really.....

 

[barongreenback]

Not a problem - best way to learn. Have you had a look at books or websites on exposure? It helps to understand the relationship between aperture, ISO and shutter speed, and the effect these can have on your photos.

 

[Bristol Pete]

I read, read and read it but it seems gobbldygook at times.......

 

[barongreenback]

Think of ISO, shutter speed and aperture as three different ways of letting light into your camera, but to get a perfect exposure they need to be in balance.

For example - you want to freeze motion so you'll need to use a fast shutter speed. As the shutter speed is fast, not alot of light can get onto the film or sensor, so you need to open up the aperture to let more light in. If this doesn't get you the right exposure you then need to increase the ISO to increase the sensor's sensitivity to light.

This works in reverse. I want to maximise my depth of field and get everything in my shot pin sharp. So I choose a small aperture. To get sufficient light into the camera I need to open the shutter for longer. ISO applies as before.

Hope that helps you understand a bit of what I'm talking about. If it does help, let me know and I can copyright it!!! lol.

 

[senu]

I read, read and read it but it seems gobbldygook at times.......

... Surely not ! Have a look Here might make a bit more sense

 

[electrolyte]

I read, read and read it but it seems gobbldygook at times.......

Pete - someone recommeded this link on another thread and it is pretty good too: 350D guide

 

[ush flynn]

also think about your focal length, use it at the longest end of that 18-55, and combine with a open aperture and you should get nice bokeh

 

[richard plumb]

also think about your focal length, use it at the longest end of that 18-55, and combine with a open aperture and you should get nice bokeh

but at the long end, the kit lens is 5.6 I think, so it'll be stopped down slightly and spoil the bokeh.

5.6 should get you reasonable DOF though if you increase the distance between the subject and background

at 55m, f5.6, shooting from a distance of 5ft, you should have around 6inches in focus - 2inches in front, 4 behind.

 

[senu]

How useful is the depth of field preview that comes with some SLRs?

I never was able to get it to work on my old Film Canon EOS and cant seem to "see" a dop with it in the ( 350D) or in the LCD post shot. Maybe Im doing something wrong ( Iknow it doesnt work in the auto mode)

 

[Bristol Pete]

I never was able to get it to work on my old Film Canon EOS and cant seem to "see" a dop with it in the ( 350D) or in the LCD post shot. Maybe Im doing something wrong ( Iknow it doesnt work in the auto mode)

Know what you mean. Using the dop icon on the dial doesnt really seem to make that much difference but you certainly can manipulate the depth with the manual focusing options. It seems that the manual also tells you to go for a lower aperture to help depth if my memory serves me well (its at home)...in the 350d manual there is a page with some chess pieces shown...

The above shots were literally my first attempt at trying to shot a pic of wha I wanted to focus on, rather than the camera, ergo my point and shoot a75. I am only too aware of how far I have to go with my skills but the help from people like Richard, Senu etc should be a great help. I have already learnt that you can take far more control of 'your' shot rather than the cameras AI in creaitve mode but need to learn a fair bit to get halfway decent pics.

Pete.

 

[Zone]

How useful is the depth of field preview that comes with some SLRs?

I never was able to get it to work on my old Film Canon EOS and cant seem to "see" a dop with it in the ( 350D) or in the LCD post shot. Maybe Im doing something wrong ( Iknow it doesnt work in the auto mode)

Works as well on my 300d as it did on my old 50e and thats very well, I wouldn't have gotten the depth of focus I did in last months competition entry without it.

Looking through the viewfinder of a SLR is seeing the image with the widest aperture of the lens attached, my comp entry was taken with the 50mm @ F18 but until you press the shutter and or the preview button the camera keeps the lens set to F1.8 so the image is nice and bright, press the preview button and the lens will stop down to f18, the image will darken and front and back will come into focus.

Pressing the preview button when you have a wide aperture set will make little or no differnece to the view throught the veiwfinder as the lens is already showing you the image at its widest setting.

 

[richard plumb]

You can do a lot more with a DSLR - I'm just starting too

but bear in mind 'with great power comes great responsibility' - you can do more, but there is more scope for mistakes too. So far I've

- forgotten to reset WB from indoors when going outside
- left it on MF so had a whole bunch of OOF shots
- not noticed the flash causing the shutter speed in Av mode to be *really* slow, so lots of blur
- forgotten to reset the ISO from 1600 when outdoors

 

[shoehorn]

It seems that the manual also tells you to go for a lower aperture to help depth if my memory serves me well (its at home)...in the 350d manual there is a page with some chess pieces shown...

There's a good bit relating to wine bottles in this post

 

[senu]

You can do a lot more with a DSLR - I'm just starting too

but bear in mind 'with great power comes great responsibility' - you can do more, but there is more scope for mistakes too. So far I've

- forgotten to reset WB from indoors when going outside
- left it on MF so had a whole bunch of OOF shots
- not noticed the flash causing the shutter speed in Av mode to be *really* slow, so lots of blur
- forgotten to reset the ISO from 1600 when outdoors

Sounds Familiar...... !

 

[senu]

Works as well on my 300d as it did on my old 50e and thats very well, I wouldn't have gotten the depth of focus I did in last months competition entry without it.

..................................

Pressing the preview button when you have a wide aperture set will make little or no differnece to the view throught the veiwfinder as the lens is already showing you the image at its widest setting.

Thanx ,got the hang of it now but I find i have to press the button first before pressing the shutter to avoid just taking the photo!
BTW your pic ( ive posted there) got me !

 

[Zone]

Thanx ,got the hang of it now but I find i have to press the button first before pressing the shutter to avoid just taking the photo!

Not sure I understand you mate!
The preview button is to help with macro and for shooting with small apertures, for example set f22 on your camera and look through the viewfinder, the lens is in fact fully open at its widest f-stop f1.8 etc so the image is nice and bright, now focus on something in the distance and then press the preview button, the image will darken and what appeared to be out of focus will/should now appear to be in focus, its just a guide so you can determine how much of the shot will and wont be in sharp focus.

Once you're happy with the composition take your shot, no need to keep your finger on the preview button.

BTW your pic ( ive posted there) got me !

Thanks for that, looking at your comment if you notice, in my description you'll see I did artificially blur the background around them, due to using f18 meant alot of the shot was in focus but I only wanted them in focus so blurred everything thing else.

 

[senu]

...What I meant was that for the DSLR, the focus ( autofocus), aperture and shutter speed (exposure) are set when the shutter button is pressed halfway down.

It is at that point that the DOF preview button is used ( simultaneously). Having satisfied oneself the dof is as hoped for, the picture can then be taken the normal way. : Ie finger off dof preview button and shutter button depressed fully.
The camera will not shoot if both buttons are pressed together for the shot anyway.
Another query: If I have a prime lens used at its widest aperture ( thereby aiming for shallowest dof, what difference does distance to subject make?

 

[Zone]

...What I meant was that for the DSLR, the focus ( autofocus), aperture and shutter speed (exposure) are set when the shutter button is pressed halfway down.

Understand now

Another query: If I have a prime lens used at its widest aperture ( thereby aiming for shallowest dof, what difference does distance to subject make?

A lot

Closer to the subject and wider the aperture the smaller the dof.
Long gone unfortunately on most lower end lens is the dof scale

For fun there is a online dof calculator here

 

[richard plumb]

on a 350d, 50mm lens wide open at f1.8

2 metres from subject, DOF is 11cm
1 metre from subject OF is 3 cm
50cm from subject, DOF is 1cm

shrinks pretty quickly