July 22, 2014, 10:35:17 PM

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Messages - Lee Jay

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31
Third Party Manufacturers / Re: A Summary of Sigma Lens Rumors
« on: July 11, 2014, 10:22:23 PM »
Why do people keep thinking that a 24-70mm f/2 is even remotely likely?

Have they not held the already behemoth Canon 24-70 2.8 mk2 or Tamron 24-70 2.8 VC, both which require 82mm filter threads just to sharply render that zoom range at 2.8?

They are modestly sized lenses.  Not big at all.

Quote
Have they not noticed that the Sigma 18-35mm f/1.8 DC is only a 2x zoom, not a 3x, and that it only needs to worry about a largest diaphragm of 35 / 1.8 and an APS-C image circle?  (HUGE difference from 70mm f/2 with an FX image circle!!)

18mm f/1.8 on crop is a harder thing to get to than 24mm and f/2.  This is because Sigma's crop lenses don't reach into the body like EF-s lenses do, so they have to have the regular back focus distance of a full-frame lens.  This makes 18mm much more strongly retrofocus than 24mm, and f/1.8 is still faster than f/2.  I doubt much in the 18-35 is driven by the aperture at the long end, and 70/2 is still only 35mm, which isn't very much aperture.  My 85/1.8 is silly tiny and has 47mm of aperture.

32
Third Party Manufacturers / Re: A Summary of Sigma Lens Rumors
« on: July 10, 2014, 08:54:11 AM »
hmmmmm...I rather like the sound of a 24-70mm f/2 DG ART....  :D

But you probably wouldn't like the weight. Or vignetting. Or price (ymmv).  Really, this won't happen, where's a reason the rest of the world builds f2.8 zooms - "faster" means accepting a unbalance not compatible with mass market production/sales.

Which is, apparently, why no one builds a 70-200/2.8, a 120-300/2.8, a 300/2.8 prime, a 200/2 prime, or anything bigger than a 24-70/2.8.

33
Lenses / Re: 5D3 + teleconverter + Telescope
« on: July 08, 2014, 11:17:31 PM »
Hi,
    Do you have problem if you only use the 5D3 + T-Ring??

    Although I usually don't use teleconverter (I usually use a barlow), but shouldn't be a problem... I do a test on my 6D + 1.4x Kenko Teleconverter (I don't have Canon Teleconverter) + T-Ring and it work as per normal. I look at all my T-Ring and none of them make contact with the DSLR pins.

    Have a nice day.

Not the DSLR pins, the contacts on the teleconverter. I have the same problem and taping the three TC contacts fixes the problem.

34
Lenses / Re: 5D3 + teleconverter + Telescope
« on: July 08, 2014, 10:22:24 PM »
Tape the contacts.  The t ring might be shorting them out.

35
Third Party Manufacturers / Re: A Summary of Sigma Lens Rumors
« on: July 08, 2014, 05:14:11 PM »
A 24-70/2 OS is the only one of these that would excite me.  The 18-35/1.8 seems to indicate Sigma could go this way.  As long as it were around 70-200/2.8 size or smaller, that would be fine.

If the Canon 24-70/2.8 had IS, I might have considered it.  But without IS, all of them are non-starters for me.  I'll just keep my 24-105 in that case, which is exactly what I've done.

36
EOS Bodies / Re: Eos7D mk2, How EXCITED will you be if . . .?
« on: July 07, 2014, 03:16:50 PM »
  • Really high performance AF system, including f/8 AF point(s)
  • Hybrid EVF/OVF viewfinder (for shooting video)
  • Good video features (focus assist, good focus performance, continuous windowing/zoom)
  • High pixel density sensor
  • High quality sensor
  • 100-400L II designed for use on this camera with a 1.4x TC while still preserving outstanding optics and AF

37
EOS Bodies / Re: Eos7D mk2, How disappointed will you be if . . .?
« on: July 07, 2014, 12:39:44 PM »
That's the physics I'm referring to – when it comes to sensors, bigger is better.

Bigger sensors aren't better in low-light, larger apertures are.  Bigger sensors work better in low-light when you can use a longer focal length at the same f-stop, thus increasing aperture.  For example, you might use a 500/4 on full frame (125mm of aperture) instead of a 300/4 on 1.6-crop (75mm of aperture).  However, if that

a smaller sensor can be as good as a bigger one when you give him more light... i can agree to that.

but... maybe it´s my bad english but i don´t get what you say. ;)

What matters for final image quality (aside from sensor performance, processing, etc.) is the total light accumulated during the exposure.  f-stop controls light intensity (illuminance), not total light.  f-stop * sensor area is thus total light, and aperture (not f-stop) controls that.  A larger sensor will do better in lower light at the same f-stop because of the larger aperture and focal length needed to frame the same subject the same way at the same f-stop.

38
EOS Bodies / Re: Eos7D mk2, How disappointed will you be if . . .?
« on: July 07, 2014, 12:13:44 PM »
That's the physics I'm referring to – when it comes to sensors, bigger is better.

Bigger sensors aren't better in low-light, larger apertures are.  Bigger sensors work better in low-light when you can use a longer focal length at the same f-stop, thus increasing aperture.  For example, you might use a 500/4 on full frame (125mm of aperture) instead of a 300/4 on 1.6-crop (75mm of aperture).  However, if that option isn't available lens-wise, then the larger sensor loses its advantage.

I often have that option available, which is why I can (and do) obtain the advantage of a larger sensor in low light.  But one must be careful to make sure such an option is available before buying into the advantage.

39
EOS Bodies / Re: Eos7D mk2, How disappointed will you be if . . .?
« on: July 07, 2014, 11:06:33 AM »
Only a little.  The 7DII sensor is quite good, I'm rarely limited by low-ISO DR, and Canon could potentially use the same sensor and still improve IQ by improving off-sensor electronics and/or using some tricks associated with the dual pixel architecture of that sensor.

40
EOS Bodies / Re: EOS 7D Mark II Announcement September 5, 2014?
« on: July 07, 2014, 08:58:03 AM »
Bring it on.  And if there is a substantial improvement in sensor technology (by every one else's standards but Canon), let us know when that will percolate up the line, especially to the 5D and 1D series.

41
EOS-M / Re: Cheap 400mm advice
« on: July 06, 2014, 02:48:37 PM »
Okay...I'll say it again.  Just because a lens has more aperture doesn't mean it has more resolving power because aberrations do matter.A large but poor device may resolve less than a smaller, better one.  Obviously, if quality is comparable, aperture rules.  That's why I sold my 127mm MCT for a 280mm aplantic SCT.

42
EOS-M / Re: Cheap 400mm advice
« on: July 06, 2014, 01:39:37 PM »
Just because a lens is faster for a given focal length doesn't mean it has more resolving power.  It does mean it has more potential resolving power due to larger aperture but aberrations do matter, and small fast mirror lenses are often much poorer optically than larger slower telescopes.

44
EOS-M / Re: Cheap 400mm advice
« on: July 06, 2014, 11:04:11 AM »
There's nothing wrong with cropping.  This was taken with a 100-400L and 2x TC on a T2i.  Still needed heavy cropping.


45
EOS-M / Re: Cheap 400mm advice
« on: July 06, 2014, 08:26:07 AM »
Filling the frame with the moon takes around 4000mm equivalent in the horizontal direction or about 2600mm in the vertical direction.

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