Messages

31

Lenses / f/2.8 telephoto lenses have better AF than slower lenses?

« on: May 01, 2012, 05:48:45 AM »

This I have culled from www. learn.usa.com (with thanks) about 7D auto focus:

"... the center AF point has a separate diagonal pair of high precision line sensors which provide even greater precision - automatically used with lenses f/2.8 or faster....."

When considering an investment in a big lens is this a consideration ie go for the f/2.8 lens rather than a longer f/4?

32

Lenses / Very long lenses could become redundant...........??

« on: April 25, 2012, 04:21:53 AM »

With high density sensors coming on stream at a fast rate image size on your computer screen increases in proportion to the square root of the Mp.
Thus when (not if!) the current 7D 18Mp is superceded with say a 24Mp sensor (the R3200 already has 24Mp but on a slightly bigger sensor) a 600mm lens becomes equivalent to a 693mm and so on.
Perhaps in say ten years time there will no longer be a need for huge focal length and Canon/Nikon will not make anything bigger than a 400/2.8 with a built in 1.4xTC!
Assuming of course they can do something about improving S/N ratio of those tiny pixels.

33

Lenses / Re: Canon 300/2.8L - non IS

« on: April 25, 2012, 03:50:41 AM »

Wiki is pretty good for this sort of thing.  Check this out if you haven't found it already.

http://en.wikipedia.org/wiki/Canon_EF_300mm_lens

Thanks.
Found a lot of useful info on suspeceded EOS lenses on this very useful site:

www.canon.com/camera-museum/camera/lenses

Recommended!

34

Lenses / Re: Are primes really more sharp?

« on: April 24, 2012, 12:19:31 PM »

I'm checking out the MTF charts, and there does not appear to be a significant sharpness edge from using only prime lenses.  Is reality misrepresented on the MTF charts?  Are they not that much better than zooms?

The inherent problem with zooms is that they have a lot more lens elements than primes.

More elements therefore means lower contrast - fact of life!

All lens elements have to be positioned correctly on the optical axis within engineering tolerances - the more elements the greater the problem of providing you with a decent lens.

 A Canon prime will always beat a zoom - sharper, lighter, cheaper!

35

Lenses / Canon 300/2.8L - non IS

« on: April 22, 2012, 05:15:27 PM »

Does anybody know anything about the history/spec of this lens?
Was there a mark II - non IS version made?
Also any info how sharp these early non IS versions were?

36

EOS Bodies / Re: Canon 650D - sensor size?

« on: April 20, 2012, 03:56:52 AM »

Just seen the D3200 (24Mp) 100% crop sample image on Nikon Rumours.
Ultra smooth - very impressive!
If the 650D comes out with say 20Mp on board it will be bad for Canon and they will have an uphill job convincing anyone new to DSLR photography to choose their brand!!
When you need 100% size images the more Mp the better.

37

Lenses / Re: Sport Photography: Targeting 400mm preferably with a zoom range

« on: April 17, 2012, 05:22:12 AM »

Option 1: This is a good zoom - sharpish at 400 stopped down to f8 but with an old IS design - but still better than your other options.
Option 2: 2xTC on a zoom - you must be joking!!
Option 3: Very sharp little lens which due to lack of IS needs to mounted on tripod/monopod for best results - not suitable for hand held sports action photos.

Recommendations:
Option 1: Wait for new 100-400 L with 3/4 stop IS which allegedly is due end of this year.
Option 2: Buy used 400/2.8 IS!!!

38

Lenses / Re: 70-200 f/4 L IS USM

« on: April 13, 2012, 10:51:30 AM »

The f/4 IS is preferable to the f/2.8 IS.
Why?
The f/4 is half the weight.
The f/4 is half the price.
The f/4 is sharper wide open than the f/2.8 is wide open.
The f/4 IS is one of those rare zooms - sharp wide open and sharp at the top end as well.
OK - if you want to look good with a big heavy zoom lens around your neck then get the f/2.8!

If you really want f/2.8 consider buying the two Canon lightweight primes - 85/1.8 and the 200/2.8.

A Canon prime will always beat a zoom!

39

Software & Accessories / Film Scanners - any user recommendations?

« on: April 13, 2012, 08:04:45 AM »

I have thousands of old black & white foll film negatives (6x6, 6x7 and few 6x9 and 645 and some 35mm Kodachromes) to scan and upload.

Can anybody please offer recommendations (Canon, Nikon, Fuji etc) for few good ones to choose from - from first hand experience?

40

EOS Bodies / Canon 650D - sensor size?

« on: April 11, 2012, 01:20:04 PM »

Any rumours on the sensor Mp size for this next body in the popular APS-C range - and when it is due out?

The 450D had 12.2 Mp sensor

500D had 15.1 Mp

550D/600D have 18.0 Mp

650D - 22 or 24 Mp?

If you are shooting smallish targets requiring cropping then increasing pixel density on the same sensor must be beneficial to image quality - same size image but more pixels covering it?

41

Lenses / Re: Used 400mm f2.8L IS lenses - good value now?

« on: April 11, 2012, 08:51:48 AM »

Thanks.

Just a thought - if the AF works at max aperture (before stopping down to the desired aperture) and since the depth of field at f2.8 is a lot less than at f4 does that mean that the 100% full size images on the 400/2.8 are "sharper" than on the other big ones?

Anybody there to correct me on this!?

42

Lenses / Used 400mm f2.8L IS lenses - good value now?

« on: April 10, 2012, 01:51:04 PM »

Just spotted this lens sold in a London shop for £3450 inc hood and flight bag and warranty - from the photos it seemed fairly described as exc++.

For a used Canon 500/4 - current model in the same condition - the current asking price would be a lot higher.

Surprising particularly as the 400/2.8 has a lot more glass and has the extra stop to freeze the action.

The current 500/4 is a bit lighter but certainly no lightweight.

Perhaps because there are a lot more 400/2.8s around and owners are upgrading to the latest version - available now.

Maybe we can expect a drop in price for used 500/4s when the new model comes available in May - allegedly?

Both are very nice lenses to catch fast moving objects but I am guessing you would get more keepers with the 400/2.8.

And with 1.4X TC I am also guessing that 560/4 images would be better than 700/5.6? Anybody out there who has used/tried out both lenses with a TC?

43

Speedlites, Printers, Accessories / Memory Cards

« on: April 06, 2012, 02:46:38 PM »

Quite a few available for DSLRs.
Any difference in performance?
In normal but heavy use do they deteriorate (ie image deterioration) after many many actuations?
If this subject has been covered before - apologies.

44

Lenses / Re: Prime VS Zooms.

« on: April 05, 2012, 04:47:21 PM »

Sorry but have to disagree.
The 70-200 f2.8 is heavy - front heavy.

The 70-200 f/2.8 II + 1D4 are well balanced

That's a heavy combination to carry around?
Better balance with a heavier body -  I agree.
Poor balance with APS-C body.

45

Lens Gallery / Re: Canon EF 500mm f/4L IS USM

« on: April 05, 2012, 04:22:13 PM »

Anybody with moon shots or contrail photos taken with the 500/4 IS?