Messages

271

Lenses / Re: Sigma 50mm f1.4 EX DG HSM....are they any good?

« on: December 01, 2011, 06:33:41 PM »

But Bryan at TDP certainly knows his way around a fast prime, and he states, "...the Sigma 50mm f/1.4 EX DG HSM Lens has proven very inconsistent for me in the focus accuracy department.  I have thrown out as many as 70% or more images from a single shoot of over 100 non-action, wide aperture shots because they were very OOF (Out of Focus)."

He also only tested one copy I should note that I don't see any where near a 70% throw away rate. Some shots will get tossed, but no more than with my 85 f/1.8.

Likewise, Roger at LensRentals.com has probably used and tested more camera lenses than most people will ever even see in their lives, and he states, "...the lens exhibits what I will term “schizophrenic autofocus”, i.e. when closer than 5 feet, it will front focus, further than 20 feet it will backfocus. This is not a calibration issue, it’s just how it is."

This one interests me more because I imagine he has seen/tested more than one copy.

But again, this guy is going shopping, not ordering online. He can cherry pick to get one with decent AF characteristics.

272

Lenses / Re: Sigma 50mm f1.4 EX DG HSM....are they any good?

« on: December 01, 2011, 06:28:39 PM »

has better bokeh

with ugly CA btw Sigma's bokeh is nothing compare to Russian Helios M40-2 analogue. If you prefer excellent bokeh - buy Russian stuff.

Sorry, I don't care for the bokeh of the M40-2. It's unique for sure, and I've seen it put to good use in some shots. But it's very distracting and 'nervous' for most shots. I much prefer the smooth, diffused backgrounds of the Sigma.

Needless to say the M40-2 is a specialty lens (manual focus / stopped down metering / adapter required). On top of that, it's the wrong focal length for this discussion, it's not nearly as sharp wide open, and it does not have nearly the contrast as any of the 50mm lenses being discussed. Again, it has a unique look and that can be put to good use at times, but it's not a substitute for the lenses being discussed.

As for CA: the Sigma is worse than the Canon f/1.4, but much better than the f/1.2L. At any rate CA is pretty much a non issue on digital where it's easily corrected. And with the typical subject matter for these lenses you often won't even need correction. In fact, now that I think about it, I don't think I've used CA correction on more than 1 or 2 shots from my Sigma.

273

Lenses / Re: Sigma 50mm f1.4 EX DG HSM....are they any good?

« on: December 01, 2011, 09:26:25 AM »

Thanks for the info everyone, the "Russian roulette" analogy convinced me I will wrestle my buddy to the ground and drag him away from the Sigma cabinet if I have to.

You'll be doing your friend a disservice.

The Sigma is much sharper then the Canon 50 f/1.4 at wide apertures, has better bokeh, and has much better build quality. The bokeh is amazing and the lens is actually usable wide open. I personally think it's the f/1.2L's equal. Some have AF issues, but if your friend is shopping in person then he can cherry pick the lens he wants on the spot. FYI, the AF motor in the Canon version is famous for having accuracy problems or just breaking over time.

I'm quite frankly surprised at the number of complaints here. Usually when the Sigma 50 f/1.4 comes up in forums the majority of reports are good.

As to AF issues...no doubt some units ship out of alignment. But I can't help but think that many complaints trace back to people struggling to use fast primes, especially since I've heard the same types of complaints from people who went with the Canon f/1.8 or f/1.4, and even the f/1.2L.

* f/1.4 is difficult for the AF system. This is true of any lens. DoF is stupid shallow at f/1.4 even on crop. On FF? Try one eyelash in focus.

* Any forward/backward movement on your part at wide apertures will move the focus away from where you want it. By the same token you cannot focus/recompose at wide apertures.

* Focus point indicators in the VF are not perfect. Usually the AF sensor points are larger than indicated. If the point is over a target which is not flat, the AF system may focus correctly but still focus somewhere you don't want. (DoF is that shallow.) 3D target areas that work just fine at f/4 or even f/2.8 may not yield the desired result at f/1.4 or f/2.

On a tripod pointed at a flat target the Sigma is about as consistent and accurate as the Canon 85 f/1.8. Perfection cannot be expected with super fast primes however. If you defocus, AF, and shoot 10 frames in a row, at 100% it will be clear that some shots are better than others even in this simple test. (I didn't have access to a Canon 50 f/1.4 when I did this. The f/1.8 is much worse than either the Sigma or Canon 85.) This is with a 7D which has an even better AF system.

I love fast primes, but all of them require some care in AF. There's something to be said for split screen manual focusing when using fast primes, and I've considered a KatzEye for this reason.

With that out of the way...I've shot kids (always in motion) with the Sigma f/1.4 with good success rates. And when you nail it...well...30" portrait prints at f/2 and f/2.8 are no problem at all, tack sharp and gorgeous.

274

EOS Bodies / Re: 5D Mark III Information [CR1]

« on: November 30, 2011, 06:55:32 PM »

Did you even read the entire post?

yeah yeah your workarounds are nice.

They're not just nice, they work. If I could buy a 36 MP DSLR and a T/S lens and consistently produce larger, more detailed prints then I can now for less then I would have to spend on a MF body alone, why wouldn't I?

And again I will point out that diffraction does not hit any format more than any other, and I don't often jump through special hoops to get the full 18 MP out of APS-C. That means I could be getting 45 MP out of FF if it was available.

f/11 should work actually.

that would be a near limit of 1.62m if my tables are correct.[/quote]

DoF calculator shows f/11 would just work with a focus distance of 5.7 ft. In the field it's not always possible to be so precise so you would probably be at f/13 for that example. But it is an extreme example.

what i think is that the "leaves counter" are to enthusiastic when it comes to more MP.
it´s not as if you get the 36MP for free.

I'm not counting leaves. I want larger prints and I'm on a budget.

275

EOS Bodies / Re: 5D Mark III Information [CR1]

« on: November 30, 2011, 06:18:35 PM »

I'm not "ignoring airy disks", I'm telling you a 36 MP FF sensor will easily trump an 18 MP one for landscapes.

and how is that possible when you use small apertures?
when you have a diffraction limit already for 21 megapixel FF sensors at f13.

Did you even read the entire post?

i want everything from 1m to infinity in focus (not uncommon for landscape images as i want forground interest).
even with hyperfocal distance i need f16 for a 24mm lens on a FF body.

f/11 should work actually. But does every landscape you shoot really need DoF from 1m to infinity? Even when I get on top of foreground elements I'm usually further than 1m, sensor to nearest element.

276

EOS Bodies / Re: 5D Mark III Information [CR1]

« on: November 30, 2011, 05:57:00 PM »

the probelm is you don´t understand what im saying.
the diffraction limit of lenses makes it just MORE nonsense to ask for a 36MP FF sensor. 

Not every landscape is shot at f/16 or f/22. Using hyperfocal focusing, T/S lenses, or focus stacking one can shoot at apertures which yield more detail.

Diffraction does not impact any format more than any other for the same desired FoV and DoF. I've spent 2 years getting a true 18 MP out of a 7D while shooting landscapes with near foreground objects, typically just by using nothing more complicated than hyperfocal focusing. That means I could get a true 45 MP just as often out of FF if such a sensor was available. Canon's T/S lenses open even more opportunities for shooting at optimum apertures yet having everything in focus from very near to infinity.

I should also point out, since this discussion includes what is/is not the sweet spot of a lens, that the final resolution of any system is not bound in the way most people think. Most people think there's a fixed number for, say, a lens at a given aperture, and if that number is lower than the sensor number then that's the final resolution. Nope. I would have to look up the exact formula, but resolution is:

* Always less than the weakest part of the system.

* Comes closer to approaching the weakest part as other parts increase.

If your lens MTF50 resolution is 60 lpmm and your sensor is 80 lpmm, final resolution will always be <60 lpmm, but increasing sensor resolution even further will actually help you get closer to 60 lpmm.

Resolution is also an MTF curve, not a single number, and modern software is exceptionally good at increasing MTF in post (sharpening). So if you're theorizing about maximum MP's from a sensor based on MTF50 numbers for a lens, you are way off what's possible.

277

EOS Bodies / Re: 5D Mark III Information [CR1]

« on: November 30, 2011, 05:35:10 PM »

yeah but only those who ignore airy discs and other phenomens would make such a across the board statement.

The 7D's pixel pitch is smaller than the pixel pitch would be for a 36 MP FF sensor, and it yields resolution gains over 12 MP APS-C sensors at landscape apertures. I'm not "ignoring airy disks", I'm telling you a 36 MP FF sensor will easily trump an 18 MP one for landscapes.

most of my landscape shots are made with f16 and above for maximum DoF.
and then the 21MP 5D MK2 is already diffraction limited.

Learn and use your hyperfocal distances.

278

EOS Bodies / Re: 5D Mark III Information [CR1]

« on: November 30, 2011, 07:33:59 AM »

3.  How many mp does someone really need truthfully?

If I had the money I would be shooting a 40 MP 645D. If I had my wish the 5D3 would be 36 MP. It may not be quite as good as the 645D, but it would allow me to produce substantially larger landscape prints at a much lower price point than MF.

Go look at the Imaging Resource 645D samples and tell me again that more MP are bad. There is a completely new dimension of detail in those studio samples. They reveal textures and fine details that don't show up on any current DSLR.

36 MP FF is still a lower pixel pitch then the 7D. I'm fine with large (i.e. 24") 7D prints to at least ISO 800. I don't need to shoot black cats in dark coal mines. I would like to get even more detail from the landscapes I wish to shoot.

279

EOS Bodies / Re: 5D Mark III Information [CR1]

« on: November 30, 2011, 07:23:50 AM »

given the rumors are true and nikon is releasing a 36MP D800 im curious what new DSLR customers will buy. for years canon was raising MP and nikon was saying less MP are better.

now it seems the positions have suddenly changed.

If this is true then for the first time I will be considering adding Nikon to my setup. Sometime in the next year or so I would like to improve my ability to make large landscape prints from a single frame. An 18 MP 5D3 will offer me nothing in this regard over my 18 MP 7D. Cry noise and DR all you want. For low ISO landscapes printed big (>30") it's all about the pixel count.

The bummer is that Canon has the best T/S lenses and they scream for more MP. I couldn't care less about movie mode Canon! You need a high pixel count FF body for landscape and studio use.

most amateurs who have no clue still think more MP will make a better image.
even after years this is still stuck in their heads.

For some applications it is absolutely true. A 36 MP sensor will produce larger, more detailed low ISO landscape prints then an 18 MP one. No if's, and's, or but's.

280

EOS Bodies / Re: What do you want from the 5D mk III

« on: November 27, 2011, 08:42:34 AM »

I can't believe more MP got so few votes. Canon needs at least one FF body dedicated to landscape and studio use. They need to match Nikon at 36 MP.

281

EOS Bodies / Re: 5dMKII vs. 60D

« on: November 27, 2011, 08:39:41 AM »

But where the 60D has those bonuses it also lacks a fair bit. Those being low light and other details that you can only really get from a FF sensor.

There isn't a detail difference between the two sensors in good light when using their full 18/21 MP resolution for 24" prints. What difference will be observed when their resolution is processed down for video and displayed at a maximum of 2 MP (1080)?

Low light I'll give you. The 5D2 is amazing in low light. But the 60D is pretty good itself.

On the other hand the 5D is a fantastic camera but not really a camera for a beginner. The learning curve is steep and you may be better off sticking with the 60D is you are not 100% dedicated to what you are wanting to do.

In what way does the 5D2 have a steeper learning curve?

As for lenses, The 60D with the Tokina and a 50mm f1.8 (around 80mm on FF) will cover most shots you will need for basic video, maybe even chuck in a cheap 55-250 lens in there too for those shots you need the reach.

Sigma 30 f/1.4 or 50 f/1.4 would be much better choices. The 50 f/1.8 is optically good, but has poor bokeh and is a pain to manually focus, which is even more critical for video.

I'm not sure shallow DoF is a good argument for the 5D2 for video either. Wide open primes on FF are difficult to use in any close situation for still photography. Manually focusing for video? Forget it. You will be stopping down any way.

282

Lenses / Re: 300mm F4L IS

« on: November 18, 2011, 08:57:20 PM »

Those people that think the 300 F/4 is razor sharp should see the output of the 300F2.8 or the 300F2.8 to understand that whilst it is good  - it is by no means the best

They can see it by stopping down 1 stop, i.e. a 300 f/2.8L II IS @ f/4 is about the same as a 300 f/4L IS @ f/5.6.

Impressive, yes. Great for someone with the money and desire to carry that much weight, yes. But realistically even at the same f/stop you can make comparable prints with either, except of course for f/2.8.

283

Lenses / Re: 300mm F4L IS

« on: November 18, 2011, 08:52:50 PM »

Acceptable sharpness is only from F/5.6.

Get your copy serviced. For real photographs I can see no real difference in sharpness from wide open, only in contrast. A test chart will reveal only a minor difference in sharpness. A properly adjusted 300 f/4L IS is brilliant from wide open.

284

Lenses / Re: 300mm F4L IS

« on: November 18, 2011, 08:50:30 PM »

Unfortunately for the 300 f4 the newer 70-300L has got better IQ, IS and bokeh.

Nope. The prime still retains an edge in sharpness and contrast, particularly at the edges. I doubt there's any real difference in bokeh (I'm open to being proven wrong by comparison images) considering that the prime is already incredibly smooth. IS is probably better on the L zoom, but then it's a stop slower to begin with. That stop can affect AF performance. While we're at it, the prime can be used with teleconverters.

The new zoom is an excellent and versatile piece of glass. But the prime still has its uses.

285

EOS Bodies - For Stills / Re: APS-C Image Quality (7d vs nex7)

« on: November 17, 2011, 09:58:51 PM »

I tried IR's studio scene at ISO 100. After downloading both samples I:

* Re-sized the 7D sample to the NEX-7 sample size using bicubic sharper.

* Applied Smart Sharpen at 100% / 0.7px.

After that the IQ advantage of the NEX-7 was much smaller then what appears in your samples. It's a 24 MP sensor so I would expect some advantage.

I also tried sharpening the NEX-7 sample a bit and then trying to "catch up" again with the 7D sample. The differences were still small. Basically the largest difference came down to more artifacts on the 7D sample, but on either the artifacts would only be visible while pixel peeping.

That said I expect a 24 MP sensor might yield a better rendition of foliage in landscape shots for larger prints. Not dramatically larger, but another 4-6" for a print which will be critically reviewed. (I consider the 7D to be a 24-30" landscape camera as is. Larger with greater viewing distance, less critical viewers, or less demanding subjects.)

We are reaching the point of diminishing returns in small format sensor resolution, where top notch glass, expert technique, challenging subject matter, and big prints are required to see any difference at all. That said I'm all for more megapixels as long as other characteristics do not suffer as large landscape prints are one of my favorite subjects.

This isn't enough to make me consider jumping ship. But I could end up with a NEX-7 any way because I would like to add a mirrorless system. I would like to see if Fuji releases an interchangeable lens version of the X-100 though. For that matter I would like to see any of the mirrorless systems embrace small, fast, high quality primes. They are too zoom heavy right now, and big slow zooms do not play to the strengths of a compact, mirrorless system.