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Messages - GMCPhotographics

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361
Lenses / Re: A New 50 Coming Soon? [CR1]
« on: October 16, 2013, 09:56:20 AM »
What reliability concerns do you have?

It broke down twice due to water/mist/dew/... getting in, when I saw the second repair estimate I decided that buying the L version is cheaper for outdoor shooting near ground level. Of course the non-L is fine if you use it indoors or very, very carefully outdoors, the iq is nearly the same and the IS doesn't make a difference near 1:1

My 100LIS macro is a little sharper than my non L was. The zoom ring on the L is a lot smoother and better geared. For macro work, this is essential. The body shell on the L is mostly magnesium / aluminium alloy, which is why it feels like plastic. It's not cool to the touch. The IS unit is great for some types of photos. When I shoot ring shots, wide open at f2.8 it's amazing. But for 1:1 stuff, a tripod is needed. The colours and contrast I'm seeing from the L lens are a lot better too.

362
Third Party Manufacturers / Re: Sigma 24-105 f/4 DG OS Outed?
« on: October 16, 2013, 09:47:46 AM »
Oh my God! ... the lens isn't even out yet but people already know it has "inconsistent AF" and that too from just knowing that it is "much heavier" and that it has "82mm filter size" ::)

On Sigma website before it was taken down:
    Lens Construction: 19 elements in 14 groups
    Dimensions (Diameter x Length): 3.5in x 4.3in
    Maximum magnification ratio: 1:4.6
    Weight: 885g / 31.2oz
    Minimum focusing distance: 45cm /17.7in
    Angle of view (35mm equivalent): 84.1°-23.3°
    Filter size: 82mm
    HSM delivers high AF speed and quiet performance
    Offers F/4 brightness throughout the zoom range
    OS (Optical Stabilizer) functionality
    Super Multi-Layer Coating reduces flare and ghosting
    Rounded 9-blade diaphragm
    Mount conversion service available
    Sigma USB Dock compatible

As for inconsistent AF, well, I had the latest Sigma 30 f/1.4 DC (ART) lens. Used it for a week and got rid of it. DPReview had similar problems with the Sigma 18-35 f/1.8 lens. The Sigma 24-105 f/4 won't be any better... of course its f/4 aperture may help to mask some of its AF problems.

You could always buy a Sigma dock and spend an hour or so fixing Sigma's poor QC for them at your expense :D

Seriously, I can't see any benefit this lens can offer a Canon user. I'm sure it's been brought out to bring a popular Canon lens formula to Nikon and Sigma mounts. For Canon users...the 24-105 f4 LIS is most likely going to be a better choice. The Canon one has been around for so long, it's very cheap for what it does!

363
in the review by imaging resource they point out that the lens is slightly sharper on a sub frame camera than the full frame one.

This indicates the center is way better than mid-frame to edges.

dpreview made the statement that both jpegs and raws from the 70d were indistinguishable from those taken with the 6d up to about 3200iso.

... if looking at them at the camera lcd, or you're really drunk and everything gets fuzzy :-p ... no, really, for certain pictures with a lot of background blur where nr doesn't have that much of an impact Canon aps-c shots might be ok @100% crop, but iso3200 is where the small sensor really drops the ball. Face it, a aps-c with this Sigma cannot replace a ff+200-400 :-o

the review goes in to detail of center sharpness on both bodies and such. I have researched this lens pretty heavily so i am pretty sure of what its qualities are.

here are the points i am making:

1) 120-300 on a crop body will act in practice as 192-480 on full frame
2) the lens sharpness, build quality are by all accounts in real reviews to be in the same category as the canon primes
3) its a stop faster than the 200-400 the consensus is that ff is 1.5 or 2 stops better than aps-c so you have a one stop equalizer
4) if you are really concerned about the depth of field, they should be very similar wide open

from what i have seen, the canon 300ii and the 200-400 are better on ff but its close, i have read that the sigma is slightly softer than the canon 300ii but not by much.

so as i said before, i think the sigma 120-300 on a crop body is a good alternative to the 200-400 on ff unless money is not a concern and you just want the absolute best that can be had

It's not a 120-300mm, please understand that. It's a 120-280mm and that's quite short. The max focal legth is the same as a 70-200mm with a 1.4x TC. This short coming magnifies with a 1.6x crop to only 450mm not a 480mm.
At close focussing distances, this lens looses a massive amount of focal length. By my measurements is around 240mm at 3m. By MFD it's even lower and not that different to a 70-200 f2.8. So lets look at those figures at close distance, on a full frame at MFD it's a 120-240mm.
Then there's the engineering aspect, it's not particularly durable. Just look back though this thread. There's been a lot of warrenty claims for such a low volume lens. I would question it's long term resell value and durability.
9/10 I was better served using a 70-200 f2.8 LIS II and a 1.4x TC. For the other 1/10 I was better served by other lenses (300mm f2.8 LIS mk I for instance).

364
Canon needs to make a 50-300 f/3.5 IS, and charge $3500 for it.  Most of you would buy that instead of the Sigma 120-300 f/2.8 OS.  Why?  Because IT'S A CANON "L"...

Why? 70-200L II + 1.4x TC gets you nearly there, is more compact and lighter, and costs less.

That's exactly the conclusion I came to when I had one. Why pay for a lens which was short on it's focal length, darker than it's stated aperture, looses a ton of focal length at close distances, has irratic and slow AF and an OS system which is pretty clunky? It's unneccisarily heavy and very bulky. I've found my 400 2.8 LIS easier to handle for some reason.
When I compared it against my 70-200 2.8 LIS II with or with out TC's I found it a far better option. Even with the 1 stop drop with a 1.4x TC.

365
in the review by imaging resource they point out that the lens is slightly sharper on a sub frame camera than the full frame one.

This indicates the center is way better than mid-frame to edges.

dpreview made the statement that both jpegs and raws from the 70d were indistinguishable from those taken with the 6d up to about 3200iso.

... if looking at them at the camera lcd, or you're really drunk and everything gets fuzzy :-p ... no, really, for certain pictures with a lot of background blur where nr doesn't have that much of an impact Canon aps-c shots might be ok @100% crop, but iso3200 is where the small sensor really drops the ball. Face it, a aps-c with this Sigma cannot replace a ff+200-400 :-o

I agree with you Marsu42. I would question any lens review which thinks that a 70D is anywhere near close to the IQ of a 6D between 400-3200iso....there is a lot more between those sensors and Aliasing filters than just that. My old 7D was questionable over 400 iso. The iso noise ramps steadily and I have yet found a 1.6 crop camera which come close to a full frame output and i'm not just talking about iso noise.

The problem I find with a lot of Sigma users these days is they emotionally fool themselves themselves that they are buying something identical for less..get one of those...only a lot cheaper...aren't I cleaver....when in reality they are buying something a lot less for less. A 200-400LIS on a full frame will blow away a 120-300 OS on a 70D in nearly every measurable area. The two are not equal and the reality is that the sigma doesn't come close. It is cheaper becuase it is cheaper. You get what you pay for.
It's a questionable lens, innovative - yes, but deeply flawed.   

366
Third Party Manufacturers / Re: Sigma 24-105 f/4 DG OS Outed?
« on: October 15, 2013, 03:46:01 AM »
While interesting, a 24-70 2.8 OS would have made an even more exciting combatant.
If you think that adding an image stabiliser will make a mediocre lens greater?
The only people this lens will please are Sigma fans and kid people who buy it that they have got a cheaper equivelent of the Canon and is there fore better and that they are smart purchasers....

367
I have been on the fence about this lens for a while. I just ordered one today from BH photo. Here is a review from imaging resource

http://slrgear.com/reviews/showproduct.php/product/1559/cat/all

They claim it is sharper on a crop body which is what I will be using it on. So you are getting similar focal range and performance as you would from the canon 200-400 on full frame. The 1 stop aperature advantage should in theory help counteract the better iso of the full frame setup and you are talking about 1/3rd the price . I will post more when it gets here.
On a crop body, you will loose a stop in iso performance and an effective stop of DOF against full frame. While your camera will state f2.8, the reality is that it is effectively dropping a stop to become a 192-380mm f4..so it doesn't really gain anything. The AF on this lens slower and less accurate than the big white and the focal length drop as the focus pulls into MFD is really quite apparent and dissapointing. I found that I was better off with a native 300mm f2.8 lens or a 70-200 f2.8 LIS with a 1.4x TC.

an f2.8 lens is an f2.8 lens regardless of whether you put it on full frame and crop out a square or on a crop body.

what i am saying is that comparing the 120-300 on a crop to the 200-400 on ff is going to be very similar in practice, standing in the same spot zoomed in they will frame about the same. without doing a shootout you can't say if the iq will be the same but i am thinking it is from what i have seen.

the 120-300 is a 2.8 so its a stop faster and will allow 1 stop lower iso in the same scene framed the same way with the same dof as the f4 lens on the ff camera

it may not be the same its hard to say without a shootout, maybe the 120-300 is better? maybe the 200-400? it would be fun to try i think the results would be closer than you think. and the thing you are gaining is $8400.00

The lens may be f2.8 but it's one part in a chain of parts. The change in camera format (full frame vs 1.62x crop) will dictate it's Iso performance, resolved detail, effective DOF and effective angle of view. A 120-300 f2.8 OS on a 7D is not the same as a 200-400 f4 L Is on a 1Dx....not even close. Sure it's cheaper but the image quality, IS sstem, AF speed, Weather sealing, Out of focus rendering, AF tracking and contrast will be worse. Expect a night and day experiance between them. If you are so sure, hire them all and do a comparision. I have a 400mm f2.8 L IS and I compared it against a 120-300 f2.8 OS on a 7D vs a 5DIII on my big 400. The Sigma lens was good but in reality it didn't come close for all the reasons I mentioned.

368
EOS Bodies / Re: EOS 7D Mark II Talk [CR1]
« on: October 14, 2013, 05:58:41 AM »
Very happy if canon 7D MkII will come with a swiveling LCD!! Think a swiveling LCD will help lot in DSLR Videography!!

Not going to happen... destroys the purpose of indestructibility and weatherproofing.
If you have the swivel open and you drop the DSLR, its going to break.
Too many creases between the swivel parts that make it less waterproof.

If you like swivel screen so much stick with the 70D.

Canon have gone on record to say that they can't make a swivelling LCD screen which is robust enough to be classified as "Professional Grade". So we won't be seeing one on a 1D or 1X series.

369
EOS Bodies / Re: EOS 7D Mark II Talk [CR1]
« on: October 14, 2013, 05:55:33 AM »
A 7DII with slight megapixel increase, awesome high ISO, AF system from 5Dmk III and same build/FPS as the current 7D...a lot of wildlife and sports shooters would be pretty pleased I think!

The problem with the current 7D (which I discovered quite early on...I was an early adoptor and then defector) is with the sensor not the rest of the camera. In fact it's a fantastic camera, let down by it's mediocre sensor performance. 18mp is fine, no issues there. But I found a lack of micro contrast, a certain milkyness and softness at 100% which I've not seen in any other Canon DSLR. I needed to selectively sharpen it's images. I concluded that this was due to an over active Aliasing filter to smooth out video footage.
I found it's iso performance quite poor too. I was seeing a stop and a half loss against a 5DII, even at Iso 400 I saw a lot of noise.
While I liked it's handling, 8fps and great AF system (for then), I found it's IQ and sensor to be lacking. Maybe this will improve with the mkII..I hope so, this camera deserves a better sensor.

370
EOS Bodies / Re: EOS 7D Mark II Talk [CR1]
« on: October 14, 2013, 05:48:51 AM »
Improved high ISO video performance would be very welcome. 7d footage at 1600 and above just looks horrible. I understand how the smaller pixel size on APS-C sensors is a limitation, but it would be SOO nice to have a Canon crop at least equal to just the Mark II as far video ISO performance.

Would it be possible to create a ~24mp APS-C sensor (so lets say pixel size of: 4µm) but use larger pixels (something closer to full frame size: 6.4µm.....or even bigger like 8µm) for the pixels designated for video, (resulting in AWESOME low-light performance)? Or does having different pixel sizes on the same sensor simply not work for whatever reason?

And I can think of a ton of photo applications for such technology as well. I'm one of those weirdos who would love a 8-10MP camera with ridiculous pixel size and thus great high ISO performance. Plus getting 14fps+ should be a breeze with that image size.

Ugh, the "large pixel" myth rears its ugly head again. Lower resolution sensors gain you nothing but a smaller file size. Full frame sensors are better in low light because of increased total surface area.


You don't seem to understand the relationship between pixel size and signal to noise ratio. All other factors equal, larger pixels collect more light than smaller ones, thus giving them better noise performance. It's not a "myth," it's physics.

It's true if everything else is equal or the same. Nikon have gained a bit of DR by placing their D/A converted earlier in the on chip processing path than Canon which is wjy they ahve a little more DR at the moment, but it's not a huge difference. Processing, chip design and on chip NR all have an effect on iso noise performance. But yes, the general rule is smaller the pixels, the greater the noise.
But here' the irony, the physical size of the pixel is the same for all DSLR's....it's the size of the bin which it sits in that collects the quality of light. This bin (with the pixel sitting at the bottom) is capped off with a micro lens which more directs light to it. Once upon a time, the iso noise was controlled by the size of the microlenses. Every time there was a jump in MP, Canon would make the micro lenses proportionally bigger to equalise the iso noise...then Nikon spoiled it all and used the largest possible (gapless) on a full frame 12 mp sensor in the D3...thus shooting themselves in the foot for a short term iso advantage. Once the public got used to that level of iso performance...they demanded al the time...even from cameras with twice the resolution, whihc has caused the entire processing path to be re-designed to extract the maximum performance. I doubt that there will be much increase in MP goign forwards....I think the Nikon D800 has proved that point. More MP means more resolution at low iso values...but really poor iso performance at high iso values. Canon is wise sticking to the ~20mp region for a while. It's the best res / iso ratio.
If we consider the slight difference in iso abilities between the 1Dx, 6D and 5DIII...it's clear that it's purely the quantity of MP which is dictating the iso abilities. Slightly lower mp = slightly improved Iso performance.
If we consider the abilities of the 1Dx, it's quite extraordinary. 18mp, 12 fps and iso 6400 is SO clean! 

371
I don't think comparing this to Canon's 70-200mm f2.8 L is a good comparison.  The 70-200mm is an excellent small venue lens.  For up to 300 or so people, it's hard to beat.

Put it on a crop body and it's definitely sports oriented.

Actually, I found I perfered my 70-200 f2.8 LIS II over this lens for a number of reasons and a worthy comparision. Popping this lens onto a crop body doesn't make it sport orientated at all...what a bizarre statement to make. I used my copy on a 5DIII and 1Dx and found that it's AF was slower and less accuate than any of the Canon white lenses (including 70-200 lenses). At the moment there isn't a crop camera with an AF system to rival the 1Dx or 5DIII. The 7D and 70D cameras have a good AF system, but it pales against the full frame cameras. Likewise, this lens can't deliver consistenly with those cameras either. It's a nice lens but it's no match for Canon's whites.

372
I have been on the fence about this lens for a while. I just ordered one today from BH photo. Here is a review from imaging resource

http://slrgear.com/reviews/showproduct.php/product/1559/cat/all

They claim it is sharper on a crop body which is what I will be using it on. So you are getting similar focal range and performance as you would from the canon 200-400 on full frame. The 1 stop aperature advantage should in theory help counteract the better iso of the full frame setup and you are talking about 1/3rd the price . I will post more when it gets here.
On a crop body, you will loose a stop in iso performance and an effective stop of DOF against full frame. While your camera will state f2.8, the reality is that it is effectively dropping a stop to become a 192-380mm f4..so it doesn't really gain anything. The AF on this lens slower and less accurate than the big white and the focal length drop as the focus pulls into MFD is really quite apparent and dissapointing. I found that I was better off with a native 300mm f2.8 lens or a 70-200 f2.8 LIS with a 1.4x TC. 

373
here's a stupid question...  with sigma suffering  auto focus issues but reportedly great  image quality...  why don't the  manual focus crowd gravitate to sigma as a value option and simply use it as a manual focus lens?

I think it would need to "feel" like a £3K before anyone would touch it :D

374
Lenses / Re: A New 50 Coming Soon? [CR1]
« on: October 11, 2013, 04:16:29 AM »
The amusing thing about the focus shift issue is that it only happens when it's stopped down.

Unfortunately, given the razor-thin dof wide open, this is bound to happen a lot :-o

The My copy is worse at f2.8, which is quite amusing because it's not that sharp at MFD and it's certainly not a macro lens.

Ok, in Canon's defense this really doesn't matter as it isn't a macro lens, it's not supposed to be optimized for mfd.

Failing that, View view isn't effected by the focus shift at f2.8...which another workaround.

Another workaround is just to skip this lens, esp for this price tag :-> ... but probably more buyers will turn up of the next Canon lens isn't f1.4 anymore but f1.8, as intended....

... if you know what you want the 50/1.2 for and how to do it, of course it's legit and a good idea, but this lens is also a prestige item: it's even available in bread-and-butter discount retailers in Germany (that's where I tested it a couple of times), and this means a lot of people are buying it because it looks cool (it does!) and *has* to be "the best" as it's f1.2.

My reasons for buying a 50mm f1.2 L was three fold. Firstly, I didn't care much for the 50mm f1.4 USM, it was cheap and plasticy, poor AF and build, very low contrast wide open and it's out of focus rendering was quite harsh. Secondly, I need the bright f1.2 aperture...faster the better and that's how I use them mostly. Thirdly, I needed the L build and reliability. If I buy a lens, I want it to last a long time. If I get 10 years out of it, it'll cost me roughly £100 / year for reliable no worry usage. If I sell it for 80% of what I bought it for....then that's even better.

375
the thing about the Canon fifties is that they are a compromise... af  on  all,  excellent image sharpness when stopped down to 2.8,  decent bokeh,  but better on the 1.2,  but no is.

 so what I want is to buy a 1.2  or 1.4 50mm  that I can use wide open that is sharp and with a beautiful bokeh...  and I really want af  and I can do without is,  but I'd like that too.   sho Canon needs to get off their duffs  and make that happen...  and I'd happily pay $2000 ish for that lens.

The 50L is not a compromise. Apparently, IS on f/1.2 is technically impossible now. The 50L is designed for bokeh, not for sharpness. Even Zeiss says that you cannot have both (in their "bokeh" document).

 I've heard that from multiple sources,  but people  live the  Canon 85's   and the 135 L for their sharpness and the bokeh...
 and the sigma 35  gets a ton of praise for being sharp wide open...  and I  know we are  comparing apples to  oranges,  but I just can't seem to accept that it  has to be one or the other
+1 here. 85L is amazingly sharp wide open.

Longer lenses are easier to be made sharper. The 85L is sharp enough wide open but not really sharp, with strong PF and reduced contrast. The 135L is long and f/2. The Sigma 35 has really poor bokeh.


My 85IIL is very sharp wide open, my copy seems to be a stellar copy. It's nearly as sharp as my 100mm L IS Macro. Even my 135L isn't as sharp as my 85IIL. It's contrast is fantastic, so I would question the copy which you are using, it must be out of spec. Yes it has Purple fringing in specuatular highlights (no where else) which is easily correctable in LR. The 50 f1.2L is a nice lens but it's sharpness is certainly lacking wide open.

135L = sharp wide open
100L = sharp wide open
85IIL = sharp wide open
50L  = not particularly sharp wide open
35L = sharp wide open
24IIL = sharp wide open

Which lens is the odd ball here? Ok, this may be my lens samples..but my 2nd photographer has the same kit and her 100L is a bit sharper than mine, but my 85IIL is sharper than hers...her 50L is a wee bit sharper than mine...but they are both the softest lens in our lens collection by a noticable margin. It's softer than any of our zooms or other primes.
As a L lens, the 50L is well built, it's AF is curiously slower than the 35L. The elements aren't that big. It' AF is certainly accurate, just a little slow to react. My mkI 24-70L is a lot snappier.
The 50L offers great flare handling, great contrast, nice out of focus rendering (bokeh is a term which only references out of focus highlight blobs). But it's sharpness isn't in the same league as my other lenses.


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