Why would i need full frame?

twotimer wrote in post #4055758
You are no longer taking the same photo but the bokeh would then be the same.

Gerhard

again sorry for my stupidity but would it appear a lot different? how would it differ ?

don't know how ppl can say it gives different bokeh then if the situation I described... its the and positioning... but with equivalent focal length and same positioning would I not get same result?

SkipD wrote in post #4055106
Methinks you didn't quite understand about the DOF.

A larger format (size of the film frame or digital sensor) will produce a shallower depth of field with a given focal length, aperture, and camera-to-subject distance. Many folks are striving to have a shallow depth of field to isolate their subject(s) from the background. Thus, the larger format (the "full-frame" 35mm film format) enables them to do this a little more than the smaller (APS-C) format.

The format has no effect whatsoever on exposure relative to the aperture used. f/1.4 on either camera format will provide the very same exposure (assuming the ISO and shutter speeds are also the same, of course).

The "bokeh" (non-measurable quality of the out-of-focus background) is primarily a function of the lens being used and the aperture setting being used with that lens. It really has nothing to do with the format.

Hmmm

If Im reading this correctly, http://www.dofmaster.c​om/dofjs.html contradicts what you have to say.

50mm f/1.4. Subject 12m away.
40D DOF = 3.13m total.
5D DOF = 5.08m total.

Sounds to me the SMALLER format will produce the shallower depth of field. Please correct me if Im wrong.

Tobiah wrote in post #4055856
again sorry for my stupidity but would it appear a lot different? how would it differ ?

don't know how ppl can say it gives different bokeh then if the situation I described... its the and positioning... but with equivalent focal length and same positioning would I not get same result?

COMPOSITION! Take a photo from a spot at 80 mm then take a photo of the same thing from the same position at 50 mm that will be the same difference that the photo from a crop versus full frame will give you. If that looks like the same photo then there is no reason to think about this any further.

Gerhard

not with a crop! will it?

if with my crop I take 2 photos with different focal lengths... I will get one zoomed picture and one not (for want of a better way of putting it...)

but with EQUIVALENT focal lengths factoring in the crop why will it be ANY different?

the answer is probably blindingly obvious to most so I apologise for this... samples would help

Tobiah wrote in post #4056076
not with a crop! will it?

if with my crop I take 2 photos with different focal lengths... I will get one zoomed picture and one not (for want of a better way of putting it...)

but with EQUIVALENT focal lengths factoring in the crop why will it be ANY different?

The composition will approximate the difference between a crop camera and a ff camera taking the same photo from the same spot. In order to get the same composition from the same spot you need to use different focal lengths with a crop and ff camera which is why the dof and bokeh differ between the two sensor types. I think you may not understand that the field of view at any given focal length is totally different between a ff and crop camera which is why I suggested you try taking the photos at the two different focal lengths.

Gerhard

twotimer wrote in post #4056138
The composition will approximate the difference between a crop camera and a ff camera taking the same photo from the same spot. In order to get the same composition from the same spot you need to use different focal lengths with a crop and ff camera which is why the dof and bokeh differ between the two sensor types. I think you may not understand that the field of view at any given focal length is totally different between a ff and crop camera which is why I suggested you try taking the photos at the two different focal lengths.

Gerhard

I think you may not understand what hes saying.

He understands that focal lengths will change. Thats why hes talking about equivalent focal lengths between two bodies.

For example;
Whats different between a shot from a 40D using the EF-S 10-22 and the 5D using the EF 16-35? FOV-wise, nothing is. Those two lenses on their respective bodies cover the same FOV. As far as DOF and bokeh go, I dont think it matters with that lens. When it comes to longer lenses, I also dont think it matters too much when youre considering the extra telephoto reach youre getting. If anything, the crop cameras will give you a smaller DOF and, it would follow, better bokeh.

AdamLewis wrote in post #4056278
I think you may not understand what hes saying.

He understands that focal lengths will change. Thats why hes talking about equivalent focal lengths between two bodies.

For example;
Whats different between a shot from a 40D using the EF-S 10-22 and the 5D using the EF 16-35? FOV-wise, nothing is. Those two lenses on their respective bodies cover the same FOV. As far as DOF and bokeh go, I dont think it matters with that lens. When it comes to longer lenses, I also dont think it matters too much when youre considering the extra telephoto reach youre getting. If anything, the crop cameras will give you a smaller DOF and, it would follow, better bokeh.

There is more to bokeh that what is being discussed here. The lens aperature blades have alot to do with bokeh, as well as the ever-intangible lens "quality" that people argue about. There is a good change the bokeh from the 16-35mm would be considered by some to be "better"

Find a thread about 50mm 1.2 versus 50mm 1.4 bokeh... you'll see what I mean. There is something real to it.

Mark IIN is differenct catagory with 5D...

Tobiah wrote in post #4055656
you didn't read my post properly... I said same positions for subject and shooter same everything ....

EQUIVALENT focal length... ie 30mm on the crop and 50mm on the ful frame (dont know if that's exact but u get what I mean)

how will ratio be any different?

Tobiah wrote in post #4055856
again sorry for my stupidity but would it appear a lot different? how would it differ ?


don't know how ppl can say it gives different bokeh then if the situation I described... its the and positioning... but with equivalent focal length and same positioning would I not get same result?

Tobiah wrote in post #4056076
not with a crop! will it?

if with my crop I take 2 photos with different focal lengths... I will get one zoomed picture and one not (for want of a better way of putting it...)

but with EQUIVALENT focal lengths factoring in the crop why will it be ANY different?

It's actually pretty simple to visualize.

Do you think a 300mm lense focussed at 30 feet will have the same bokeh as a 50mm lense focussed at 30 feet?

You can crop the image taken with the 50mm lense to have the same field of view, but the DOF fall off will not be similar at all.

There's your answer

Tobiah wrote in post #4055831
guess I'm saying with ff cameras they put there best technology...

I'm not claiming to know a lot at all just here learning...


i d be interested to see the article that guy reffered to about the ff is better with cheaper glass than crop with better glass...

I'd always thought was other way round....

Ken Rockwell (author of that article) is an enthusiastic amateur who often distorts facts and does not understand that about which he writes. Save yourself some time and get real information. Ken is entertaining, if not factual.

Full Frame vs. Crop image related differences.

http://www.outbackphot​o.com …hnique/essay07/​essay.html

AdamLewis wrote in post #4055864
Hmmm

If Im reading this correctly, http://www.dofmaster.c​om/dofjs.html contradicts what you have to say.

50mm f/1.4. Subject 12m away.
40D DOF = 3.13m total.
5D DOF = 5.08m total.

Sounds to me the SMALLER format will produce the shallower depth of field. Please correct me if Im wrong.

I stand corrected.

Using the same focal length, you are correct.

What I should have said is using lenses that provide the same field of view at the same distance, the larger format will have a shallower depth of field. In this example, use a 50mm lens on the 40D and an 80mm lens on the 5D. you would have the same basic image - same perspective because of the same distance, same coverage because of choice of focal lengths. The image from the larger format will have a shallower depth of field.

That's right SkipD. Whether it's a good or bad thing depends on how much DOF you want. Many of the more vociferous commenters on the difference seem to be after the thinnest possible, but not everyone wants that.

The huge depth available from digital P&S cameras has revolutionised photography of scale models for example, where you can get in very close and still get good depth. It can make photos of models look much more realistic.

The only thing I know without getting technical, is that ive used a 350D, 30D & now a 5D, I have used "consumer" lenses & now L grade, I have tried L grade lenses on the 1.6x bodies & the results are good, but I have NEVER seen the level of detail that I am getting by using the same lens with the 5D.

I have also found that a consumer lens when mounted on the 5D actually becomes a lot better, not worse.