Messages

76

EOS Bodies / Re: Canon 6D or 7DMKII?

« on: February 26, 2013, 03:32:43 AM »

They're two very different cameras aimed at very different uses. If its moving fast, getting the frame at the exact right moment and in perfect focus are the most important factors to look for in a body. If its stationary, timing and focus aren't difficult, so sensor performance is the most important factor to look for in a body.

The rumours for the 7D mk II suggest it will be more of the same - crop, very fast frame rate, very fast/good AF with great tracking, and for something which isn't a 1 series camera, very solid build. In other words, if you have crop glass that you want to use, or you want a 'cheap' body which can shoot action well (in other words, something in the ball park of a 1D X/5D3 in terms of AF/FPS, but not IQ) , then the 7D series is a much better buy than the 6D.

But if you're prepared to skimp on everything that makes the 7D series great in the world of crop cameras for single frame picture quality (slower/static subjects), then the 6D with its full frame sensor is a much better bet (even if Canon come out with a new killer APS-C sensor, this generation of FF will be better).

If your car shots are static and you're not tied to EF-S glass, I'd recommend the 6D.

77

EOS Bodies / Re: 7DII and D400 Specs

« on: February 26, 2013, 02:40:33 AM »

I just love speculating that the 7D 2 will be APS-H to see the APS-C crowd reactions

it's like a wind up toy that you wind up and let go and they bounce around all over the place make lots of noise then calm down eventually... until you wind them up again!

But seriously, forgive me for my ignorance, I know you like the APS-H, but are there any particular benefits of the 1.3 crop factor compared to the 1.6 or FF? Or is it a connoisseur thing?

APS-H is a nice middle ground; better IQ than 1.6, better reach than FF. On the other hand, its worse IQ than FF and worse reach than crop.

Now FF isn't only a production reality (there were no FF cameras around when Canon introduced the APS-H 1D classic), but it is also capable of very fast frame rates in the shape of the 1D X. And APS-C has an advantage over APS-H other than reach; native lenses.

78

EOS Bodies / Re: 7DII and D400 Specs

« on: February 25, 2013, 06:41:45 PM »

There is a part of me that thinks Canon may differentiate the two by offering slightly fewer megapixels but better low-light performance in the 7D, as they have done with the ID-X.

That would make the 7DII a more interesting offering, from my perspective.  If it can come within 1.3 stops of the 1D X (i.e., right at the theoretical difference between APS-C and FF, vs. the currently greater advantage of the 1D X), coupled with a high-density AF sensor (e.g. 41 points with 20 crosses) and improved metering, that'll be an impressive camera...

That would be awesome ... I do hope 7D II will be a 1.3x crop sensor

AMEN BROTHER!

By 1.3 stops, I believe Neuro meant the ISO performance. 1.3 stops equates to the difference between ISO 256 and ISO 100 - which is the theoretical difference between a 1.6x crop APS-C camera and FF - this is due to the 2.56 times greater surface area (read: light gathering area) of FF.

Canon may change tack, but so far they haven't once changed the size of a sensor in a DSLR line. If a camera comes out named 7D mk II, it's very likely to be 1.6x crop.

Ps - I really hope Canon resist the temptation to take their 1.6x crop sensor up to 24mp. It'll suffer from softness due to diffraction from f6.0 onwards - mount an f5.6 lens on there and you've got little in the way of options. Even the legendary 300/2.8 II with a 2x TC III will underperform, and leave you with just one aperture option if you want to attempt to utilise all of those megapixels. Leave the MP lower, and let those lower processing overheads allow them to push the hardware of the small mirror and shutter to its limits.

79

Lenses / Re: Why aren't zoom lenses faster than 2.8?

« on: February 25, 2013, 05:47:49 PM »

Has anyone tried actually searching for patents / designs for zoom lenses that are faster than f/2.8 35mm equivalent so that we could get a realistic idea of the size and/or cost?  Surely someone out there has made such a design.

Here you go: http://www.adorama.com/HSHC50110.html

Hasselblad MF lens 50-110/3.5-4.5, designed for a 44x33mm sensor (0.76x crop). In 35mm speak, its equivalent of a 38-84/2.66-3.42

$5,595, 1.6kgs, 152x103mm, 95mm filters.

80

Lenses / Re: Why aren't zoom lenses faster than 2.8?

« on: February 25, 2013, 03:34:06 PM »

I resized and re-uploaded the photo

Thanks

81

Lenses / Re: Why aren't zoom lenses faster than 2.8?

« on: February 24, 2013, 11:41:37 AM »

Although, we might still have to disagree on the conversion of apertures to 35mm equivalents. While converting the focal length to a 35mm equivalent makes sense (with the preponderance of different sensor sizes, it's good to have a commonly accepted way of understanding focal length), converting the aperture causes confusion.  At the same focus distance, a 30.5mm f/2.8 on a G15 has essentially the same background blur and requires the same shutter speed as a 30.5mm f/2.8 lens on a 7D and a 30.5mm f/2.8 lens on a 1Dx. In other words, a 30.5mm f/2.8 lens doesn't change any of its attributes when the sensor changes in size.   Therefore, there is no need to convert it to a 35mm equivalent.   The 30.5mm f2/8 is already a 35mm equivalent for every exposure and depth of field measurement.

If they're all cropped to the same angle of view, and printed at the same size. If not, we're talking about very different systems which cannot be compared in such simplistic terms.

If you use the effective focal length in 35mm terms to represent angle of view, lets get one thing straight - the aperture has to be adjusted too, otherwise you're no better than Panasonic's marketing department were with their FZ200:

82

Lenses / Re: first trip to England any recommendations ?

« on: February 24, 2013, 10:23:16 AM »

Also worth considering places like Stonehenge, and for scenery, the lake district or Scotland are great. On the castle front, also consider Windsor Castle and Warwick Castle - although you'll end up with loads of tourists in the shots. Stratford on Avon (Shakespeare's birth place), just around the corner from Warwick Castle is full of interesting old buildings.

https://www.google.co.uk/search?q=windsor+castle&hl=en&source=lnms&tbm=isch&sa=X&ei=PywqUdPzF-OL0AWNzoH4Bw&ved=0CAoQ_AUoAQ&biw=2560&bih=1377

https://www.google.co.uk/search?q=warwick+castle&hl=en&source=lnms&tbm=isch&sa=X&ei=VCwqUd-1PMeb0QXbi4CICg&ved=0CAoQ_AUoAQ&biw=2560&bih=1377

https://www.google.co.uk/search?q=stratford+on+avon&hl=en&source=lnms&tbm=isch&sa=X&ei=GCwqUcG6C8bIhAe7_4DYBQ&ved=0CAoQ_AUoAQ&biw=2560&bih=1377

A wide angle such as the 17 TS-E you mentioned would be great for some of these locations.

83

Lenses / Re: Why aren't zoom lenses faster than 2.8?

« on: February 24, 2013, 09:06:01 AM »

The "amplification" is not "turned up" for the smaller sensor. A 6x4mm sensor is no more noisy (or "amplified") than a 6x4mm region of a 35mm sensor. Images from the smaller sensor are (theoretically) about as noisy as a crop from a larger sensor.

The reduction in noise has to do with sampling density and averaging, not amplification.

The smaller the photosite, the less light it gathers - therefore less electrical signal is generated, so it will need a higher amplification before being fed into the A/D converter. If we are comparing the 12MP G15 sensor to a 4.6x bigger diagonal 12MP D3s sensor, not only will the FF sensor with 21 times as much area collect 21 times as much light, but each photosite (pixel) will gather 21 times as much light - which means 21 times less amplification is needed to get the same ISO's - so ISO 1600 on FF equals ISO 80 on the G15 in terms of noise.

However, if we're talking about a 12MP G15 vs a 253MP FF (that same pixel size scaled up to FF), the amplification should be identical. That scenario is where your statement of sampling density and averaging are correct.

Usually its a combination of the two as the number of MP are almost never identical in these comparisons, as are the size of each individual pixel.

ps - I was talking about comparing the entire imaging system - FF sensor, FF lens uncropped to a compact camera

84

Lenses / Re: Why aren't zoom lenses faster than 2.8?

« on: February 24, 2013, 05:12:15 AM »

In 35mm terms, its 6.1-30.5/1.8-2.8 lens is the equivalent of a 28-140/8.3-12.9 lens. Nothing too special.

Don't want to go off topic, but in 35mm terms it is still an f/1.8 - 2.8 lens.  It might have an equivalent field of view as a 28-140mm lens.  But the shutter speed is based on the f/1.8 to 2.8 aperture, which is pretty good.  The equivalent background (or lack of) is what you'd expect from a 6.1 - 30.5mm lens (which is largely independent of sensor size).  That is, you'd have similar background blur at 30.5mm at f/2.8 on G15 as you would with a 16-35mm zoomed to 30.5mm at f/2.8 on a 5Diii.  And in dark shooting conditions, shooting macro, or when capturing action with the fastest possible shutter speed, the ability to have more in focus for a given aperture is sometimes just as important.  (And besides, in post production it is easier to blur a background than add more detail in).

In a round about way, just trying to say that the aperture range of a lens should be viewed independently of sensor size.  From there, most sensible photographers can use their own judgement as to whether a particular system/sensor size is suitable for their purpose.  Need more background in focus, shoot m43 or the G15.  Need more background blur, shoot medium format (or adjust in post production).  Need it just right, shoot full frame.

Imagine this scenario - Canon releases an EF-S 400mm f/4 with image quality, build and price equivalent to the EF 400mm f/5.6.  Even though some might say it is still a "f/5.6 equivalent", most people would instantly see the benefit of the faster aperture.

As Radiating pointed out, these smaller sensors have their amplification turned up to make their ISO ratings match the apertures. ISO 1600 on a G15 at f2.8 and 1/100th of a sec will match ISO 1600 on a 5D3 at f2.8 and 1/100th of a sec for exposure. But I'm sure no-one here disputes the fact that the smaller G15 sensor will produce much more noise at the same ISO's. Its simply because the amplification is turned up much higher to compensate for the much smaller imaging circle projecting much less light onto the sensor.

If the imaging circle is a fraction of the size, only a fraction of the light is projected onto the sensor.

While it is a 6.1-30.5/1.8-2.8 lens, it only covers a small imaging circle. To put it into context of a FF setup, it is factually incorrect to only scale up the focal length. The whole system has to get scaled up - so it becomes equivalent of a 28-140/8.3-12.9 lens in terms of focal length, DoF and quantity of light. And to complete that, you should also factor in what the sensor does - its ISO 80 to 12,800 sensor is the equivalent of a FF sensor which operates between ISO 1600 and 270,000.

I wouldn't get involved with blurring backgrounds in post, it will never look right. Instagram will never replace a good lens on a DSLR - just take the photo with the right camera and the right aperture. If you need more DoF with a FF setup, stop the lens down. Shooting at f32 will cause all sorts of diffraction issues, but so does f6.9 on a compact with an equal number of MP. You can always crank up the ISO and NR, and then set the sharpness to 10 in true compact style to ensure no fine detail remains.

Canon already have a 400/4 lens out there - its a FF DO lens, and costs five times as much as the f5.6 version.

85

Lenses / Re: Could we ever see leaf shutters in EF lenses?

« on: February 22, 2013, 10:42:12 AM »

The leaf shutter will not cause vignetting, unless it is located closer to the sensor.

Good point, thanks for correcting me.

86

Lenses / Re: Could we ever see leaf shutters in EF lenses?

« on: February 22, 2013, 05:28:22 AM »

Whats the advantage of a leaf shutter over the one now im EF lenses?

No EF lens has a shutter in it. Canon DSLR's have a focal plane shutter - that is a shutter which is just in front of the focal plane (the sensor). These work by sweeping vertically over the sensor. At a slow shutter speed, its all nice and simple - the first 'curtain' sweeps across the lens, allowing the light to hit the sensor. And after a bit of time the of shutter being open, the second 'curtain' the sweeps across the lens, closing it to light. The curtains can only cover their ground at a set speed, so the shutter speed is controlled by how long after the first curtain the second curtain is triggered. At the flash sync speed, the second curtain is triggered when the first curtain has completed its movement, which means there is just the tiniest moment when the whole sensor is exposed - that is when the flash fires. At faster speeds (typically 1/250th of a sec or faster), the second curtain has set off before the first curtain has finished, so the sensor is never entirely exposed - if a single flash was to fire then, part of the frame would be exposed without the flash. Up at the fastest shutter speed, there will usually be just a tiny slit of an opening between the two curtains, sweeping its way over the sensor. To get high speed sync to work at such shutter speeds, the flash fires at a low power multiple times to get the entire sensor exposed to flash light.

A leaf shutter is usually located inside the lens, and its life is easier as it is typically placed at the narrowest part of the light path, by the aperture. And it works in much the same way as aperture blades do - it is circular, and it starts off closed, opens up to the diameter of the aperture, and then closes again. This means that at any shutter speed there will always be a time where the shutter is fully open - hence the very fast sync speeds available with such a shutter. But the fastest shutter speed reduces at wider apertures as the shutter can't cover all that extra ground as fast, and it does lead to an increase in the vignetting as detailed in my previous post.

Having both available, and using whichever one is best for the situation (with or without flash) would give the best of both worlds.

87

Lenses / Re: Why aren't zoom lenses faster than 2.8?

« on: February 22, 2013, 04:18:02 AM »

Canon makes a wicked 35-3500mm f1.7 IS lens for HDTV... The only problem? You need a trunk to carry it and it costs $200K 

http://www.canon.com/premium-lib/movie/t002/index.html

It looks like its this lens you've found:

http://www.canon.co.uk/broadcast/tv_lenses/studio_field_lenses/DIGISUPER_100_xs/index.aspx?specs=1

9.3-930mm/1.7-4.7, designed for a 2/3" sensor. That's a 3.93x crop factor to convert to 35mm terms, so its effectively a 36.5 to 3650mm lens, with an aperture varying between f6.6 and f18.4 - very impressive stuff (especially having a 100x zoom and being able to crop into an area just 1.38cm x 0.78cm with its built in 2x TC enabled), but it doesn't fit the bill as being equivalent to a FF zoom with an effective aperture bigger the f2.8.

Going bigger seems to be the only option. A lens like the Hasselblad 50-110/3.5-4.5 seems to be a good bet. In 35mm speak its f2.5 at the wide end of its focal range.

88

Lenses / Re: Could we ever see leaf shutters in EF lenses?

« on: February 22, 2013, 03:06:04 AM »

There already is a patent for adding more pins to the EF mount, but it looks like its for video purposes:

http://www.canonwatch.com/canon-files-patent-for-new-electronic-contacts/

An in-lens leaf shutter in a couple of high end lenses would be very nice. At smaller apertures it should be possible to get flash sync at the fastest shutter speed the shutter allows, and at larger apertures it should still be much faster than at 1/250th of a sec - probably around 1/1000th of a sec.

However, leaf shutters do add an additional type of vignetting at faster shutter speeds - when they're operating at their absolute maximum speed, the centre of the frame is open from the start of the exposure right the way through to the end - but go to half way out on the sensor, and 1/4 of the time into the exposure the sensor finally gets light hitting it, and 3/4 of the way through, it closes again - so at that part of the sensor, there's only 50% of the light. At the extreme corners, the aperture only opens momentarily, so close to 0% of the light hits it. Therefore it would be nice if there was an option to select which of the two shutters is used if such a lens is mounted - leaf shutter for flash work, and focal plane shutter for non-flash work.

89

Lenses / Re: Why aren't zoom lenses faster than 2.8?

« on: February 22, 2013, 02:44:02 AM »

How come the G15 is a 1.8-2.8 and doesn't weigh a 100lbs? I actually wouldn't mind a variable aperature zoom like the G15's. why don't they do that?

The G15 has a relatively small sensor with a 4.6x crop factor, and the lens as a result has a very small imaging circle. In 35mm terms, its 6.1-30.5/1.8-2.8 lens is the equivalent of a 28-140/8.3-12.9 lens. Nothing too special. Small imaging circle lenses have been doing this for years - most camcorders with tiny 1/6" sensors have quite big zoom ranges, yet they open up to about f1.8 at the wide end.

But your question about variable aperture makes sense. These constant aperture lenses such as the 70-200's are pushing the limits at 200mm due to the entrance pupil opening up to almost the size of the front element, but down at 70 you get the impression they're held back. It probably would be possible with just some minor tweaks to make a 70-200/2.0-2.8 lens.

As around 50mm seems to be about the sweet spot for easy to make large apertures, zooms at the other end of the range such as 16-35's might be possible with f2.8 at 16mm, and getting slightly larger, again to about f2.0 at around the 35mm mark.

90

Lenses / Re: Tilt Shift Lenses - Looking for Advice

« on: February 21, 2013, 02:10:51 PM »

Fair enough, I didn't include your entire post in my quote, however, this part of your comment is factually incorrect:

The 17 TS-E isn't all that sharp wide open

This thread is only about tilt and shift lenses. I was answering the original question in this thread, and I wasn't comparing the 17 TS-E to other lenses at that focal length, I was comparing it to other TS-E lenses - and it does fall short of the 24 TS-E II and the 90 TS-E when it comes to sharpness. After all, Hector1970 in his original post did state:

I love sharpness I would like to achieve back to front sharpness for landscapes.

However, if you take my statement out of context, it does read wrong. Quite clearly, the 17 TS-E is pretty much in a league of its own amongst similar focal length lenses.

Here is my entire post, where you can clearly see that one part of one sentence you're so keen to pick up on in context, comparing it only to different focal length tilt and shift lenses:

The relatively new 17 and 24 II both have independent rotation of tilt/shift axis, which makes them much more useful that the previous generation TS-E lenses. While landscape and architecture can be taken with a wide range of focal lengths, usually you're looking at the wider end for those applications. The 24 TS-E is optically the best of the bunch, while the 21 year old 90 TS-E is also optically excellent, although it is typically used for product photography. The 17 TS-E isn't all that sharp wide open, and doesn't respond too well to TC's. Even stopped down to f11 with the 1.4x TC, its nowhere near as sharp as the 24 TS-E II is wide open:

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=487&Camera=453&Sample=0&FLI=1&API=4&LensComp=486&CameraComp=453&SampleComp=0&FLIComp=0&APIComp=0

Obviously ultimate sharpness is less important than having the correct focal length for your application, but the 24 TS-E is possibly the pick of the bunch for your requirements.