September 23, 2014, 12:45:04 AM

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Messages - rs

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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.

Lenses / Re: 70-200 f2.8ii or i
« on: July 03, 2014, 03:00:14 AM »
..Neither have direct equals in other bands which says a lot about the quality of these lenses.

uhmmm..  the Nikon 70-200 f/4 VR may not be pro quality build but it's optically quite a good performer and is, for example, one of the better lenses to use on a D800e for maximum resolution.

So there's one.

And the Tamron 70-200 f/2.8 VC is no slouch either, turning in a similarly good performance.
That's 2 other options or at least one if you want an EF mount.

Current generation FF bodies are unable to differentiate the Canon 70-200 II and Tamron 70-200 VC lenses by much of a margin. But if you compare these lenses with TC's fitted, that small gap in performance opens up to a huge void.

I have actually thought about getting a 400 mm f/4 prime (big white that unfortunately does not exist)

EOS-M / Re: Cheap 400mm advice
« on: July 02, 2014, 07:25:28 AM »
How do you get the TC function to come up.  I didn't know that was possible... and even now that I see it... I don't know how to replicate it.
Only some lenses have it. It's hidden away in the focal length drop down box. For almost every zoom lens tested with TC's, they're only tested at the long end of the zoom with a TC, so for example the 70-200 II is tested at various native lengths from 70 to 200, and then again at 280 and 400, which are the the lens at 200 and a 1.4x mk II and then 2x mk II. And then again at 280 and 400 for the mk III extenders.

Things get odd with the 200-400 due to its built in extender. Full explanation here, and when you get your head around it, you'll see there's no other way of presenting it with this tool without adding additional drop downs for TC's:

Quote from: The Digital Picture
There are some things you need to know about the Canon EF 200-400mm f/4 L IS USM Ext 1.4x Lens image quality test results. The built-in extender with external extender compatibility complicates complete image quality presentation of this lens in our tool. So, here is what I am showing:

The first tested copy of this lens is presented as two lens samples – sample "1" and "2". Sample "1" is tested at all focal lengths (including those with extenders) with the built-in extender switch set to 1.0x (not being used) with the only exception being the first of the two 560mm focal length tests – the one that indicates "1.4x Extender Int". Sample "2" results were all captured with the built-in extender in place – the switch was set to 1.4x with no exceptions. Sample "2" results showing one of the "III" extenders in use also had the built-in 1.4x in use. You will notice the ultra-high focal lengths in these results.

The second tested lens is presented identically as sample "3" and "4".

EOS-M / Re: Cheap 400mm advice
« on: July 02, 2014, 06:17:24 AM »
Why do you want to take photos of the moon, especially low resolution ones? If all you want is the moon,
here are some images from when I was comparing lenses on the 5DIII and the SX50. You would do much better with the SX50 than a moderate 400mm on the 5DIII. The 600 (300mm/2.8 II + 2xTC) was the best for me. From top to bottom 100-400mm, SX50 at nominal 1200mm, 600mm, and Tamron 150-600 at 600mm. (The Tamron was taken, obviously, at a different time, and under more hazy conditions and at a poorer phase for seeing detail).

Thanks for posting the images for comparison. Yeah I see your point but I just want to give it a bash. Not entering any competition or anything. Just practicing for the sake of it. I do want to try capturing the moon in different phases like you've demonstrated here. Like I said I don't want to spend a ton of cash on a 300 f/2.8 but rather wanted to just use what I have. Guess 400mm ish is not enough then. So you think the 2x extender then?

If you're going to get a TC, only the 1.4x will have a genuine use with your lenses and bodies for day to day use. And the 2x won't be everything you need for the moon - to fill the frame you need somewhere in the region of 2000mm (FF). The 2x with a 70-200 on crop is only 640mm equivalent.

Here's what a cheap (even including the mount it's cheaper than a mk III TC) one metre telescope can do with a 40D, some cropping and PP:

The rumor says:

"new telephoto lens"

which could easily mean a telephoto lens design that currently doesn't exist as well as an update of one that does.

Why not announce a new APS-C telephoto lens with a new APS-C camera?

because there is no point in an aps-c telephoto

If there is no point in an APS-C telephoto then why does the EF-S 55-250 exist?

Because going as wide as 70mm on a crop camera is still quite tele, putting the lens out of general use for many people. 55mm at the wide end makes it more of an all round tele zoom for crop users.

Once you drop much below around 70mm in focal length, there are packaging and cost advantages to a smaller imaging circle than FF.

A 70-xxx, 100-xxx or 200-xxx has somewhere in the region of a 1% weight and size saving with the reduced rear element size required for the EF-S imaging circle - the lens elements further forwards are all identical in size. So why not just make such a lens FF compatible, and therefore sell it for less due to increased sales?

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