August 21, 2014, 10:36:53 PM

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Messages - rs

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Lenses / Re: Sigma 50mm Art 1.4 Focusing problems
« on: July 22, 2014, 11:03:49 AM »
All Sigma lenses have focusing problems! I had two of the a 24-700 and 70-200 last versions - I sent them to be calibrated with my body and then everything was ok.

This is FALSE.  I have two Sigma lenses that have had no focusing problems.  (I don't consider improving AF accuracy with in-camera AFMA to be part of a "problem.")

But the 50 Art that I received did have erratic, unreliable AF that could not be helped with AFMA.

So, if online chatter can lead to Sigma fixing the problem, we aren't helping by using sweeping, ranting statements such as "All Sigma lenses have focusing problems!"

I stated this before and say this again: I did not and do not have AF problems with my 50Art. And I agree with YuengLinger.  It is wrong to make statements like "All Sigma lenses have focusing problems!" - it is not true. Sigma did a great job with the Art series.


My second copy of the Sigma 50/1.4 (non Art) focuses very accurately and consistently. The same can't be said of the first though  ::)

Lenses / Re: Sigma 50mm Art 1.4 Focusing problems
« on: July 22, 2014, 07:23:17 AM »
But it's annoying to buy a fairly expensive AF lens which you're expected to fiddle around with on a docking station and even then seems best used, in the case of many copies at any rate, in MF mode.

Why do you think AFMA exists on Canon cameras? To address the same problem that the docking station is for.

The problem isn't QC it is engineering tolerances and the fact that neither camera nor lens are all made the same. There is copy variation between each camera and lens. This means that whilst AFMA might be +5 for a given lens on your camera, that same lens might be -5 on my camera and that same lens might be +0 on someone else's camera.

Like we've said soo many times before, it's NOT about afma ... Sigh, it's the  inconsistency ! Please print this message and tape it on your fridge.

AFMA is there because there is inconsistency. Canon recognizes that there is inconsistency in camera/lens manufacture and thus introduced that feature to allow people to tune their own camera. If every lens was the same, AFMA wouldn't be needed.

AFMA is there for consistent errors. Inconsistent errors cannot be corrected with a simple offset.

Software & Accessories / Re: Help..
« on: July 22, 2014, 02:38:22 AM »
Have you tried extracting the downloaded file, and placing the extracted .fir file on the CF card, as per the instructions in the PDF file?

If that's all there, it won't hurt trying out the firmware update on your friends already updated 7D - it will recognise the update (if done correctly), but will decline the update as it's already on the latest version. If that happens and the same CF card and contents doesn't work in yours, then something fundamentally is wrong.

Without images showing the problem, we can only speculate.

My take is it could be some sort of flash sync issue - are you using third party triggers or lighting at or near the x-sync speed?

Again, just pure speculation. Please post some images showing this issue.

EOS Bodies / Re: Patent: 45x Zoom for Waterproof Camera
« on: July 20, 2014, 11:49:41 AM »
It's difficult for me to imagine a reason I'd ever buy a gopro.

It's a very focused product aimed at a very different market to the point and shoot alternatives. And it really does depend upon what you do as to whether its way of working is of any use to you. One things for sure - it fills that void of a fisheye portable camera which is waterproof. Just no LCD without spending extra.

At the moment I find I'm using my GoPro more than my DSLR's - but that's down to what I get up to rather than it being a better traditional photographic experience.

EOS Bodies / Re: Patent: 45x Zoom for Waterproof Camera
« on: July 20, 2014, 03:23:28 AM »

Want a useful underwater hyperzoom?

Full frame fisheye (180° diagonal) to 100mm.
You can get most of that right now by combining any of the current generation of waterproof compacts with a gopro

EOS Bodies / Re: Patent: 45x Zoom for Waterproof Camera
« on: July 19, 2014, 06:02:34 PM »
Is that f9 at the long end?  :o

EOS-M / Re: Next official EF-M Lens
« on: July 18, 2014, 09:24:19 AM »
Admittedly I have not looked into Speedboosters but I wonder how they increase stops of lights passing through them? Changing perspective such as what an extender does I get but extenders degrade the amount of light rather than boost it.
A teleconverter enlarges the image projected by the lens. This is much like moving a projecter further away from a projector screen - much of the image is missing from the screen, and even though the quantity of light coming out of the projector is no different, what is on the screen is bigger and dimmer.

Do it the other way only works if you're using a lens designed for a larger format. It telecompresses the light into a smaller imaging circle, producing a brighter, smaller image. Same concept as a projector throwing out too big an image for a screen, so you move it closer.

Obviously using a larger projector screen (read: sensor) in the first place would have captured the same quantity of light, even through the intensity per unit area on the screen (sensor) is lower.

Or a different way of looking at it is the focal length has changed due to a teleconverter or telecompressor, but the physical aperture still has the same diameter. Therefore the aperture ratio (f stop) has to change.

A telecompressor is just a way of using a smaller sensor to do most of what a larger sensor would do with that lens natively. Even though numbers all get shifted around (focal length, aperture ratio, ISO, but not physical aperture or shutter speed), the end result should be the same (presuming the telecompresor ratio is that same as the crop factor, and you tweak all the settings to create equivalence).

How about distortion? I really like 0 distortion on the macro lenses. My most used focal lengths are 35,50,70 and 105(which would probably be 135-150 on 70-200 lens).

Here's the distortion at 135 on both lenses:

And a comparison of the mk II at 135 and the 135/2:

Lenses / Re: EF-S 10-18mm Image Stabilizer System
« on: July 10, 2014, 07:43:47 PM »
Maybe it's just saying that this is the body and focal length it's tested at?

Yes, that's how I read it. They've got results of 4 stops, and they're just explaining the exact scenario they used to achieve these results - a get out clause to avoid everyone demanding a full 4 stops of IS at all focal lengths with any old lightweight body.

EOS Bodies / Re: The Always Hidden Camera at the World Cup
« on: July 10, 2014, 02:36:15 AM »
There were at least 7-8 so called hidden cameras during Arg-Hol semifinal game. 'Canon' brand name was written on the cover material. A lot of them were the middle part of the pitch rather than corner areas. Testing a crop body from distance  may be ? No rain before and during the game and all the Nikon body and lenses used were without cover btw.

Those photographers probably read CR, and are just playing with us  ;D

Lenses / Re: your experience of buying very old EF L lenses
« on: July 10, 2014, 02:34:05 AM »
It's worth bearing in mind that unlike some other really old lenses, the 70-200/2.8 is still a current lens - so even if they stopped making it today, parts will still be available for a number of years.

However, if it was my money I'd opt for a 70-200/4 IS. For my style of shooting, IS at those focal lengths is much more important than one stop of light. And the f4 IS is still very much in the 'tank built pro grade' league.

As well as the sharpness and handling advantages listed by other posters, the f4 IS is 'fully weather sealed' unlike the f2.8 non IS (whatever that Canon marketing phrase means; no IP rating is given for either lens). Optically, the non IS f2.8 lens is not as bad as the mk I IS version, but its not quite in the same ballpark as the f4 IS at f4, and nowhere near the mk II at f2.8. If you need very fast shutter speeds and/or a very shallow DoF from a zoom lens, and stabilisation and ultimate resolution aren't important to you, the 2.8 non IS could be worth getting over the f4 IS if you can financially handle potential repair costs. In every other situation, I'd recommend just getting the f4 IS.


EOS Bodies / Re: Patent: Canon 55mm f/1.4 & Other Primes
« on: July 07, 2014, 05:22:20 AM »
Is there anything in the patent that says that these are EF lenses? Could they be EF-s or M mount?

The image height is 21.64mm - that's the radius of the image circle (or half the diameter). EF lenses are designed to cover a sensor with a 43mm diagonal, so these are FF lenses.

EOS Bodies / Canon EOS 5D Mark IV To Feature 4K Video?
« on: July 03, 2014, 06:47:28 AM »
Quote from: Canon Watch
Just recently a rumor surfaced stating that Canon may announce the EOS 5D Mark IV at the beginning of 2015. Now I have been told (thanks) that the successor of the EOS 5D Mark III could feature 4k video. The feature is going to be implemented, so the source, to further push the 5D into the videographers domain.

Currently Canon is featuring 4k on the EOS-1D C (Adorama | B&H Photo). It would be a more than welcome move if the 5D Mark IV would deliver 4k! Canon added HD recording to the EOS 5D Mark II, let’s hope the EOS 5D Mark IV will make the next step. Just to remind: full HD has a 1920 x 1080 resolution, 4K has a resolution of 4096 x 2160.

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