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Messages - Stephen Melvin

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1
Lenses / Re: Tamron 150 600 woes
« on: August 12, 2014, 06:57:18 PM »
Another "reverse engineering" thing that bit me was the Nikon-Canon adapter I own and works perfectly on my Mk II. It has the chip on it for AF confirm.

It absolutely fails on my Mk III, to the point where I cannot use it at all.

2
Lenses / Re: Tamron 150 600 woes
« on: August 12, 2014, 06:54:25 PM »
One thing that's worth a mention is that Canon's mount is long out of patent protection. Contracts, of course, are a separate issue.

I wonder why I've never had an issue with a Tokina lens. I mean, other than the focus and zoom rings turning the wrong direction.

3
Lenses / Re: Tamron 150 600 woes
« on: August 12, 2014, 02:07:43 PM »

No, they don't. Why would Canon ask them to build a lens for their cameras and then not give them the specs they need?
Canon asked Tamron to build EF lenses?

Yes. Canon and Nikon both use Tamron to build (generally low end) Canon-branded lenses.

4
Lenses / Re: Tamron 150 600 woes
« on: August 12, 2014, 12:19:59 PM »

i was told (possibly by a tamron rep ) but don't hold me to that .that the problem is the fact that canon will not let tamron have the lens algorithm table to get it right most of the time ,whereas nikon and sony let them have access to theres .i don't know if this makes sense or is even the truth but most problems with this lens seem to be coming from canon users ,the pics i am seeing from the nikon ones are spot on ,with hardly any complaints from nikon users at all .
   i borrowed one for a day and in all honesty i was not impressed with a/f at all and would rather use a 400mm f5.6 plus 1.4tc on my 1D3 to get the  reach .


The problem with that oft-repeated theory is that Tamron makes lenses for Canon. They do for Canon as well. They couldn't very well do that if Canon didn't give them all the information they needed, could they?
They reverse engineer, with obvious shortcomings.

No, they don't. Why would Canon ask them to build a lens for their cameras and then not give them the specs they need?

Remember, it's Sigma that has AF problems with nearly all of their lenses. Most Tamrons work fine.

5
Lenses / Re: Tamron 150 600 woes
« on: August 12, 2014, 10:56:53 AM »
i was told (possibly by a tamron rep ) but don't hold me to that .that the problem is the fact that canon will not let tamron have the lens algorithm table to get it right most of the time ,whereas nikon and sony let them have access to theres .i don't know if this makes sense or is even the truth but most problems with this lens seem to be coming from canon users ,the pics i am seeing from the nikon ones are spot on ,with hardly any complaints from nikon users at all .
   i borrowed one for a day and in all honesty i was not impressed with a/f at all and would rather use a 400mm f5.6 plus 1.4tc on my 1D3 to get the  reach .


The problem with that oft-repeated theory is that Tamron makes lenses for Canon. They do for Canon as well. They couldn't very well do that if Canon didn't give them all the information they needed, could they?

6
EOS Bodies / Re: Canon Doing Market Research on Medium Format?
« on: August 08, 2014, 09:59:21 AM »

In order for there to be a noticeable image quality difference, you have to double the diagonal. So you'd be going from 43mm to 85mm, give or take.

I don't think the lenses would be a huge issue. They could rework some existing designs to throw a larger image circle. A "normal" lens would be 85mm. The job would be easier if they went with a mirrorless design. I doubt the 85 f/1.2 would throw an 85mm image circle, as designed, but I'll bet an 85 f/2 wouldn't be a difficult engineering challenge.

They hardest part would be the business case. a 36 x 48mm sensor would be pointless. The image quality difference would be imperceptible. You'd need a 55 x 70mm sensor to make things worth the effort. But then costs would be too high.

It seems unlikely to me.
Not altogether true you have to view it as "a complete system" and you have to decide what is important a. dynamic range or b.resolution. Sony has managed to improve resolution on its CMOS sensors (include any camera with a Sony sensor) by decreasing the pixel pitch but to compensate has better controlled noise particularly dark current noise which improves apparent dynamic range i.e. that range is truly useable. On a 36X24mm sensor the current happy medium is around 5um however the cinematography favorite the Alexa is around 8um because they want better dynamic range & color slightly at the expense of resolution and that image is projected far larger than most photographs.

The relationship between pixel pitch and line pairs per mm is also crutial ideally you want to match the two so you could be doubling this between small & large pixels hence a "complete system" would aim to maintain the relationship and make improvements to other elements like processing, glass types, light wells, micro lenses, fill factors etc.

The other factor to keep in mind is MF will have less depth of field than FF so auto focus will be far more critical and for bigger lenses speed will be the challenge for AF in sports & other fast moving subjects. Bigger glass means more expensive glass and I agree logic would say do away with the mirror to shorten the back focus and reduce the size.

MF only has reduced DOF if the lenses are built proportionally. Currently, no MF system is capable of producing shallower DOF than a Canon system. It was true in the film days, and it's even more true now.

With the same level of technology (for example, putting a roll of Tri-X in a Nikon and another roll into a Bronica), you have to double the diagonal for there to be a noticeable difference in the image quality.

My wall is full of very large prints made from cameras from the 30D to the 5D, Mk II. I'd challenge anybody to tell which ones were made with the FF camera vs the APS cameras. There just isn't that big of a difference between APS-C and FF. I only switched because of the lenses.

7
EOS Bodies / Re: Canon Doing Market Research on Medium Format?
« on: August 07, 2014, 12:28:02 PM »
In order for there to be a noticeable image quality difference, you have to double the diagonal. So you'd be going from 43mm to 85mm, give or take.

I don't think the lenses would be a huge issue. They could rework some existing designs to throw a larger image circle. A "normal" lens would be 85mm. The job would be easier if they went with a mirrorless design. I doubt the 85 f/1.2 would throw an 85mm image circle, as designed, but I'll bet an 85 f/2 wouldn't be a difficult engineering challenge.

They hardest part would be the business case. a 36 x 48mm sensor would be pointless. The image quality difference would be imperceptible. You'd need a 55 x 70mm sensor to make things worth the effort. But then costs would be too high.

It seems unlikely to me.

8
Remember the torture test Kai over at DigitalREV put a 7D through? That is one seriously tough camera! The Mk III seems to be equally robust. I doubt the 6D is, though. For the most part, cameras seem to be tougher than you'd think.

9
EOS Bodies - For Stills / Re: Fun Arias rant on APS-C vs. FF
« on: July 31, 2014, 09:53:54 AM »
When Zack implies that shooting APS-C is a good as Nikon full frame, that doesn't automatically apply to Canon APS-C sensors.  We're lagging behind.  But when you look at other modern sensors (such as Fuji) that are being put into camera systems in which quality lenses are being specifically designed for APS-C sensors (such as Fuji), you'd be surprised at the high image quality.  Modern APS-C sensors are excellent.  Rather than being defensive and negative, we should become proactive and demand Canon pick up their game.

I was about to make that point about the lenses. Nearly 15 years into the digital age, neither Canon nor Nikon has bupkiss for APS lens lineups. Unless you absolutely love 18-xxx megazooms. Still no fast portrait lens. Still no fast normals. Still no fast short telephoto zooms (70-200 equivalent). Fuji and m4/3 have fleshed-out lens lineups already. And Pentax has some amazing APS format lenses. Small and sharp. Professional lenses.

What does Canon have? A bunch of idiot parrots saying "Use an L lens." Well yes, if you're using FF. But for APS format cameras, they have absolutely nothing, despite having an awesome camera in the 7D. A pro grade camera with no pro grade lenses. Lovely.

I'm probably going to move to the Fuji or a M4/3 at some point. Not that I don't love my Mk III and high end lenses. But at some point, you get tired of lugging around heavy gear. I have a great assistant, for now. Once these smaller formats catch up -- and they will -- the FF format will look like a dinosaur. N and C have had a huge head start, but they've been resting on their laurels. Shame on them.

10
Third Party Lenses (Sigma, Tamron, etc.) / Lomography Petzval Lens
« on: July 30, 2014, 12:35:40 PM »
Received it about a week ago. Really difficult to work with. The focus knob only goes 1/4 turn to go from 1M to infinity. And it's in a really awkward position; especially if you try to take a vertical. Which is why I've pretty much only taken horizontals with it.

Focusing with the Mk III's screen is about hopeless. I use Live View with my Zacuto finder and zoom in. This can be quite successful. The depth of field is very shallow. Surprisingly so, considering that I shoot my 85 f/1.2 wide open most of the time, so I know what to expect, normally.

The lens is very, very sharp dead center. Even at f/2.8. But you don't buy such a lens for sharpness. You buy it for its character, and it has character in spades. What's so interesting is how quickly the image starts to diffuse once you start to get away from the center. Look at the hands in some of the pictures.

I wish they'd built this lens more conventionally. Helical focusing and an AF-confirm chip would be such a huge boon. If they wanted more authenticity, I think it would have been neat if the lens elements were uncoated.

Anyway, I love the images. So I'll be using this lens a lot. It makes me slow down and compose, and I wind up shooting just a few images, generally. I realize this seems rather contradictory. This lens is definitely
not for everybody. It's slow to use and a bit frustrating at times. But the images...

11
Lenses / Re: Sigma 50mm Art 1.4 Focusing problems
« on: July 24, 2014, 01:46:03 PM »
Back when I was shooting APS format cameras, I found myself buying a number of Sigma lenses, because Canon wasn't making what I needed. I want to say about 4 or 5. Each and every one had focusing issues. The 18-50 f/2.8 started front focusing on one end and back focusing on the other, about two years after I bought it (this was long before Canon brought out the 17-55). The 30 f/1.4 always back focused (and this was years before AFMA). I did a lot of manual guesswork with that one.

The 50-150 f/2.8 always back focused. I got into a routine where I would turn the focusing ring a little after AF was done. Worked pretty well.

Then I got a 7D and did an AFMA of +20 (!) and suddenly this became a gorgeous lens.

And then the flex board went out on it and it wouldn't AF at all. That was an expensive fix.

My 12-24 FF lens was fine, but that was probably the deep DOF and soft IQ.

Glad to see Sigma is nothing if not consistent. Never had a problem with a Tokina (love their lenses!!) or Tamron. Hell, even my cheap Phoenix macro gave me no issues, ever. But Sigma? I'm done.

12
Third Party Manufacturers / Re: Adopting a MF system.
« on: July 22, 2014, 09:48:07 AM »
Absolutely serious question:
What value do you see in buying and using this equipment? Those Kodak backs are very old, and have a high crop factor.

Is it the resolution? If that's the case, I promise you you'd be better off buying a Nikon D810, which would be better at pretty much everything. Focus? Check. Resolution? In the real world, check. Dynamic range? Oh my God, yes. Lens selection? By a country mile. Shallow DOF control? Oh yes.

I can think of no logical reason to buy into this system.

13
Nothing like a bit of Screamo to start the morning.

14
EOS Bodies / Re: Eos7D mk2, How disappointed will you be if . . .?
« on: July 13, 2014, 02:57:14 PM »

Maybe Canon has decided to finally make some pro-grade lenses to go with the 7D, and is waiting until they can launch both at once.
All the Pro grade lenses (the "L" lenses) will work on the 7D.  Do you mean that they will make pro grade EF-S (crop sensor) lenses?  To do that, they will need a pro grade body.  A 1Dx with an APS-C sensor.

Of course that's what I mean. 15 years into the digital age, and Canon makes a superb APS format camera (the 7D), and yet no professional grade lenses designed specifically for the format. Meanwhile, M43 and Fuji are rounding out some really good lens lineups for their smaller cameras.

This whole "L lenses work on APS sensors" thing is beyond idiotic. You knew full well I meant designed for the format. Only Pentax has bothered to make the appropriate lenses for their APS format cameras. But Canon continues to add 18-xxx mm superzooms. They should have had a 58mm f/1.2 lens designed for portraiture a decade ago. A 50-135mm f/2.0 would be an amazing sports lens. And of course a 15-45mm f/2.0. And that's just for starters.

Nikon's been just as stupid, and for their most profitable cameras. There's no direct upgrade path for either camera company. Madness.

15
Software & Accessories / Re: Adobe Photoshop & LR CC deal
« on: July 12, 2014, 08:35:29 PM »
I have PS 5, which is all I need or expect to need for some time to come. LR has been on a two year upgrade cycle, give or take, for about $80. So this "good deal" will be a $120 price increase, if they force me to buy it, instead of just upgrading Lightroom.

I seem to remember this originally being $20 a month. In any case, I wish they'd make this thing optional.

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