April 19, 2014, 02:15:01 AM

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Messages - GMCPhotographics

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Lenses / Re: New Wide Angles Lenses in 2013 [CR2]
« on: April 17, 2014, 06:18:17 AM »
The trick here is you have to realize that optical designers can do very funny things with focal length, like making an 800mm lens that's only 461mm long, or "retrofocusing" design with an effective focal length that exists entirely outside the lens.
The "focal length divided by aperture" rule is true, but the definition of focal length is more than meets the eye.

I'm sure the video guys here would point out we would all be better off using T-stop anyway.

The word "telephoto" indicates that a lens' focal length is longer than it's physical length. So a 135L is a telephoto lens, but a 85L isn't. Many photographer's assume that a "tele" indicates a longer focal length, but it doesn't. It is possible to have a fairly wide telephoto lens.

I learnt something today. So the 40mm pancake is in fact a telephoto lens. Who knew?

Yup! While the 50mm f1.4 USM isn't a telephoto either!

Lenses / Re: Review: Sigma 50mm f/1.4 DG HSM Art
« on: April 17, 2014, 06:16:48 AM »
This is much the same as the 35L vs 35A debate.....  If you want a sharper lens with harsher bokeh go with the Sigma Art Lenses... if you want an overall smoother rendered pic go with the Canon equivalent.   Though the 35A is  sharper (I owned it for a few months) the 35L rendered the better image to my eyes...  Sharpness isn't everything.

I agree with your 35L vs 35A conclusion BUT honestly all this talk about the bokeh of the 50L being better seems like unfounded assumptions.

In every test I have seen the Sigma 50A outperforms the Canon 50L  in bokeh. The Sigma lacks the aberrations and flaws, and business that the Canon shows while delivering the same punchy contrast in the background blur.

It's like somehow people have already decided that the Canon has better bokeh despite having evidence that seems to be to the contrary.

Well, that's an opinion of other photographers on this forum which is probably best kept to your self. Unless you want to single out someone specifically and start a flame war.

I have used a 50L for many years. Taken countless professional weddings and a number of landscapes with it.
I found for landscape work, there are sharper options, especially when stopped down. Professionals aren't particularly bothered is Sigma makes a slightly better optic than Canon... pros buy Canon for several reasons, they are generally built to a far higher standard. In 7 years of wedding photography I've never had an L lens fail on me. I abandoned Sigma several years ago due to their comparable fragility, heavy weight, poor flare control and inconsistent AF. I've owned 6 sigma EX lenses over the years and sold them all. 5 of them went back to Sigma due to poor reliability.

Sure Sigma may have made their new 50 and 35 to better specs...but I'm done with them as a brand, I won't trust my photographic business to their products anymore. I bought a 120-300 OS to see if they had improved and found all the old issues. So I re-sold that particular lens and I'm not even going to bother with the new 35 and 50...why? Because I've had 7 years + of sterling service from my Canon 50 and 35...so why introduce a new risk? I'm happy with the results I see and my photos and services are selling. Your mileage might vary.

Canon non-EF Lenses (TS-E, FD, etc.) / Re: Canon TS-E 17mm f/4L
« on: April 17, 2014, 05:52:08 AM »
Here's a few to my recent shots from Somerset, UK. I tend to use my 17L to correct perspectives in architecture:

That's the moon in the last shot :D
This is one of my favorite "occasional" lenses....when you need one...you need one. When you don't, there are far easier lenses to use!

5D MK III Sample Images / Re: 5D MK III Images
« on: April 17, 2014, 05:31:28 AM »
A few from Somerset, UK this week:

5DIII, 70-200 f2.8 LIS II and TS-e 17L...I'm sure you guys are smart enough to work out which shot used which lens ;-D

Lenses / Re: Sigma 180mm 2.8 Macro
« on: April 16, 2014, 12:24:02 PM »
Can anyone verify the real world focal length of this lens. When I compared my old Sigma 180mm f3.5 macro to the Canon version, I found my Sigma was a lot wider at 1/2 macro.

Lenses / Re: Review: Sigma 50mm f/1.4 DG HSM Art
« on: April 16, 2014, 12:22:03 PM »
One key issue with the 50L is the "focus shift" that occurs if the lens is used near minimum focus distance at apertures between 2 and 4. Since this is quite a common setting in portrait shots, I wonder why so many people recommend the 50L so much as a portrait lens.

And the second thing which wonders me even more, is that none of these reviews checked whether the 50A suffers from this same focus shift issue. Since the issue appears to come from spherical aberrations which are less present in the 50A there is a good chance that the 50A is less affected, but the many tests and comparisons between 50L and 50A might as well take a closer look.

The 50L's focus shift occurs at min focus distance (very close). So for head and shoulder portraits, which is usually shot over 1m, then it's a minor issue and very slight. The focus shift only occurs when stopping down, as the aperture gets to f2.8 it's at it's worse. Most people are using this lens either wide open (not an issue) or stopped down to f8/f11 in the studio under flash light, so it's also not an issue.
If one uses this lens for it's intended purpose, its fine. Sure it's Canon's softest L lens (they still make other non L lenses which are softer), but it's not a lens designed to be critically sharp. It's about charector and bokeh...but unfortunately so many amateur photographers get totally hung up on sharpness and lens charts.

If you are best served with the Sigma, knock your self out and get one. If you fancy a 50L, likewise. But don't think that either lens will bring peace and happiness....it's just a lens at the end of the day.

Lenses / Re: Review: Sigma 50mm f/1.4 DG HSM Art
« on: April 15, 2014, 04:55:41 PM »
There aren't any really obvious winners and losers here, just a personal choice of where you want your strengths and compromises to sit. I've used a 50L for many years and It's been a reliable work horse. I don't reach for it when i'm after critical sharpness. No, I reach for it when I want that certain creamy bokeh type of look. It's that kind of lens and it does it really well. It's contrast, colour fidelity, build and flare control are exceptional. I've not had any build issues with mine and neither has my 2nd photographer. But i have heard of some other pro's having issues with the front dust cap coming off with the hood. This I believe was due to a defective batch from Canon and were offered free repairs.

Has anyone else noticed the focal lens difference between the Canon and Sigma. The 50L is slightly long for a 50mm....closer to a 55mm to my eyes. The Sigma looks a little wide, maybe 45mm? Could be an issue if you are pairing it with a 35mm and not a 24mm.

I'm not a big 50mm user any more. I far prefer using a 35mm / 85mm combo on a pair of 5DIII's than a 24mm / 50mm option.

Lenses / Re: Teleconverter advice
« on: April 14, 2014, 05:23:42 AM »
I also have the Teleplus Pro 300 DGX. Trust me, the quality is not as good as the Canon 1.4x TC III.

Yep, I agree. The general rule of thumb I stick to is to use the same brand tele converter as the lens. If it's a Sigma 120-300 f2.8 OS....then use a Sigma tele converter...they are designed to work together. If it's a Canon lens, then use the latest and best available...a Canon 1.4 mkIII.

I have and had most tele converters available and my 400mm f2.8 LIS is best served with the new Canon 1.4x mkIII and a 2x. I get the best IQ and AF out of those combinations...by IQ I mean the whole Image quality package: sharpness, distortion, contrast, colour, flare, detail, corner quality etc, not just ...oh it's a bit sharper.

Lenses / Re: Review: Sigma 50mm f/1.4 DG HSM Art
« on: April 14, 2014, 05:18:20 AM »
"Pretty large for a 50mm f1.4"

Well it does have 13 elements, (that do wonderful things!).

I wonder how it handles flare and direct sunlight as a consequence? The 50 f1.2 L is pretty amazing in this regard. I used to have a Sigma 100-300 EX DG f4 and a 70-200 f2.8 EX DG and they were both pretty hopeless with flare and direct sunlight. Contre-Jour was impossible with those two lenses...so i wonder how the new 50 f1.4 art fares in this regards. My old Sigma 12-24mm lens (an amazing optic, with with an odd balance of benefits, features and issues) was pretty good with flare, although not a patch on the Canon 16-35IIL

Is this the ver I or ver II? I had ver I and altough I liked it, it had a large soft spot in the centre of the frame even at small apertures and softness on the left hand side. I found the lens too wide for landscapes but great for travel and tight spaces as you describe which is the best use for this lens.Size and weight balnce great on the 5D MKII. For landscape the 17-40 would be better since it takes filters easier but this lens is the king of tight spaces.

Yep, it's a stunning lens. Utterly unique even after all these years (it was one of the original ultra wides in the dawn of the digital age). It's still a marvel, it's so rectilinear corrected, it still offers a very unique view on the world which is more than the sum of it's focal length. On a full frame it's a gob-smacking 12mm and that's really quite an amazing feat. It's really an f11-f16 lens due to it's softness, and unfortunatly it was designed and made during Sigma's worst years of quality control. I cherry picked my copy out of a batch of 6 in the shop...and some of them were shockingly bad. Mine was the best of the bunch.

Lenses / Re: EF 24-70 f2.8L II Shutter Speeds
« on: April 07, 2014, 06:29:19 PM »
If I remember, I read somewhere that human hands can't stabilise a camera more than 60 lines per mm.

Lenses / Re: Which lens now?
« on: April 07, 2014, 06:26:53 PM »
I know what a lens is...not sure about a lense though....

Lenses / Re: Philosophical question about Sigma Lenses - Why?
« on: April 03, 2014, 05:06:41 PM »
Just out of curiosity thanks to a conversation in Marketing 101 - why would a company like Sigma create products for other brands, specifically lenses for Canon? I'm curious about the thought process that went into a decision by such a company to create accessories and devices for someone else's products since they already have their own line of camera bodies...

There have been a bunch of good answers from other people, so I'll take a different tack.

I'm not sure the question needs to be "philosophical"...I think it really just boils down to a question of mere survival. If it wasn't for the fact that Sigma made lenses for other brands, there probably wouldn't be a Sigma! ;-P I mean, when you get right down to it, Sigma's cameras have basically "nil" for market share. Of the total camera market, Canon, Nikon, and Sony command some 87-92% (depending on which years data you reference, from the last 10 years). On average, there has been about 11.5% "other" market share, and from that 11.5%, Sigma doesn't even come up in any searches, graphs, charts, or tables, indicating it's share of that share is only a few percent.

Without lenses, Sigma's ~1-2% market share in cameras wouldn't be enough to keep them alive. They wouldn't have any money for R&D of any kind, let alone for lenses. Sigma is a lens company first and foremost, and they have become a good lens company. They are a camera or general photography company a distant second.

So, why does Sigma make lenses for other brands? Because THAT is their business: Lenses. :)
Says a lot about Foveon doesn't it.
Some capitalist have surmised that DSLR bodies are loss leaders to sell lenses, which is assumed where all the profit margins are.

Landscape / Re: Post Your Best Landscapes
« on: April 02, 2014, 03:51:30 PM »
Taking a bamboo ride on Yulong River, Guilin - China
Hmmm, a very nice shot...probably my favorite i've seen all year. Very nice. I particularly like the slight fade in the sky. I don't know if that was natural or added on post...not fussed, but it adds just enough ambiance to a blank sky, while not detracting from the lovely reflections in the foreground. If I had to vote, this would get my fav ;-) Thanks for sharing!

EOS Bodies / Re: Patent: EF 85mm f/1.2L III and Others
« on: April 02, 2014, 05:34:17 AM »
Apologies guys, getting my loca and coma confused....but it's not something which is much of an issue with portraiture, I've never pointed this lens at the stary night sky. With all large aperture prime lenses, one has to take the vices with it's benefits. It's not a perfect general lens but it takes some fine portraits.
I have used it for landscape work, which showed that my copy is very sharp wide open and stopped down. But it's heavy for an 85mm prime and it's max stopped down aperture of f16 is a bit short for star bursts

Not many users of this lens are that fussed by weather sealing. Adding a rubber ring doesn't really add much to it's weather sealing capacity. I've ridden my 85IIL in quite heavy rain and not had any issues:

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