Learning Curve

[astral]

I am not sure if this should say learning curve, or re-learning curve.

I have been trying out the 50mm F1.4 on my Canon 40D, making an equivalent focal length of 80mm

It must be 20 years since I owned such a fast lens. All my zooms are F4 at the very best.

I took a few experimental shots at a dinner part recently. Most worked well, except for this one.

Those muffins in the middle are nicely in focus, and the rest shows the bokka of the lens, even at F2.8,

but not really the effect I wanted.

I guess I have to re-learn about depth of field.

[The Vulcan]

Yep, the DOF on an 80mm at f2.8 is very narrow! In this case no more than a few inches. But after all, differential focusing is the whole point of using an 80mm lens.

The subject matter was inappropriate for the lens in use (or vice versa)

Fast primes certainly make you think a lot more about DOF, hyperfocal distance etc eh?

Attached shot with my 85mm at f1.8 showing the very shallow dof which is what I was after.

[Nordlys]

I've recently bought an EF135mm F2L, my first prime too since I shifted from MF SLR to AF. At 135mm focal length its DOF is probably much shallower than 50mm at F1.4 at close range. I've ued this lens many times for indoor portrait. Its DOF is so narrow at F2 or even at F2.8 it's so difficult just to get one eye right in focus and you have to use AI servo focusing mode with this lens (rather than one shot AF) or slight movement in either the photographer or the subject and resulting change in even the slightest distance from the camera to subject (in a matter of milimeters) will make everything in the frame blurred. It's also extremely difficult to get both eyes in focus at F stop greater than F2.8 even when you think you're shooting at straight ahead 90 degrees angle from the subject.

With full frame, sometimes I wish its DOF isn't that narrow when on trips because when you take family snap you want to show where the photo was taken. Often it requires F8 or smaller aperture (even with wide angle lens) to get the view in the far-away background as sharp as the subject in the foreground, needlessly promting raising ISO in the broad daylight to compensate for the slower shutter speed.

Those muffins in the middle are nicely in focus, and the rest shows the bokka of the lens

It's called "bokeh".

astral will go through re-learing curve when he changes his 40D to full frame.

Edited July 29, 2008 by Nordlys

[astral]

I've recently bought an EF135mm F2L, my first prime too since I shifted from MF SLR to AF. At 135mm focal length its DOF is probably much shallower than 50mm at F1.4 at close range. I've ued this lens many times for indoor portrait. Its DOF is so narrow at F2 or even at F2.8 it's so difficult just to get one eye right in focus and you have to use AI servo focusing mode with this lens (rather than one shot AF) or slight movement in eit

[astral]

I've recently bought an EF135mm F2L, my first prime too since I shifted from MF SLR to AF. At 135mm focal length its DOF is probably much shallower than 50mm at F1.4 at close range. I've ued this lens many times for indoor portrait. Its DOF is so narrow at F2 or even at F2.8 it's so difficult just to get one eye right in focus and you have to use AI servo focusing mode with this lens (rather than one shot AF) or slight movement in either the photographer or the subject and resulting change in even the slightest distance from the camera to subject (in a matter of milimeters) will make everything in the frame blurred. It's also extremely difficult to get both eyes in focus at F stop greater than F2.8 even when you think you're shooting at straight ahead 90 degrees angle from the subject.

Thanks for that tip on the use of AI servo focusing.

With full frame, sometimes I wish its DOF isn't that narrow when on trips because when you take family snap you want to show where the photo was taken. Often it requires F8 or smaller aperture (even with wide angle lens) to get the view in the far-away background as sharp as the subject in the foreground, needlessly promting raising ISO in the broad daylight to compensate for the slower shutter speed.

I wonder what ISO speed you use normally.

When I first started photography I did not have a meter, the rule of thumb

was 1/125th at F8 on a cloudy day, or 1/125th at F11 on a sunny day.

This was using ISO 125 in the variable climate of the UK

astral will go through re-learning curve when he changes his 40D to full frame.

I shall not be taking that step.

Although the 5D is a nice piece of equipment I do not want the extra weight,

and I do find the built in flash of the 40D very useful.

[Nordlys]

I wonder what ISO speed you use normally.

As low as possible, usually ISO100 - 200 in daylight and 200 - 400 in dawn/dusk. 400 indoor with room light but occasionally 800 - 1600 in circumstances where tripod would normally be necessary. Frankly, it's hard to tell the difference in noise level between ISO100 and 400 if you're shooting in daylight.

I shall not be taking that step.

Although the 5D is a nice piece of equipment I do not want the extra weight,

and I do find the built in flash of the 40D very useful.

Upgrading to full-size would open up a whole new world (I think). Remember with cropped sensor camera you're literally taking all shots with wide (wider) angle lens therefore deeper DOF than full size. You need 31.25mm lens to get the same field of view as 50mm lens on full-size.

Edited July 30, 2008 by Nordlys

[astral]

Upgrading to full-size would open up a whole new world (I think). Remember with cropped sensor camera you're literally taking all shots with wide (wider) angle lens therefore deeper DOF than full size. You need 31.25mm lens to get the same field of view as 50mm lens on full-size.

I guess I already made that decision when I moved from my full frame film camera, to cropped digital.

How far should I go?

I started with a camera using 120 film and something like an 75mm f4.5 lens.

[Nordlys]

How far should I go?

Well, 5D is very cheap now (55,000 Baht for body at Fotofile).

I've paid more than 120K Baht for it when I bought it, when fotofile used to sell it at hefty 170K Baht.

But seriously, if you already have the lens asset (other than EF-S) why not use them to make the most out of what it was designed for? Sure 5D should be heavier than 40D but by how many grams? It's often the lens that you use that makes it heavy if you have a fast L lens like my 24-70 F2.8L. If you already have non EF-S lenses, it's not that big a leap forward to shift from 40D to 5D.

[astral]

I am probably locked in now, with the 10-22mm and 17-85mm EF-S lenses.

[Kf6vci]

Depth of Field might be useful, but generally, when you need high lens performance, most slower lenses have better MTF curves and most lenses peak between 5.6 and 8.

I had a Zeiss 1.2/85 and hated it. with a 2.8/180 I often got the necklass in focus, but the eyes were out of focus.

The best fast lens I ever used was a Zeiss 2.0/110 mm medium format with the Hasselblad 2000 F System. Got some great DOF shots. Show the blurred fore ground, then the sharp main object, then the blurred back ground.

Just use the 1.4 only as needed. Even with a shutter speed of 1/8000 often such an aparture provides disappointing photos.

[thaipapajim]

Ok OK forget all this technical stuff. Get to the nitty gritty --- but what did the muffins TASTE like????