October 01, 2014, 12:32:19 AM

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Messages - rs

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16
Easy answer.

1. 7d and 500mm f/4 is 800mm equivalent and f/5.6 equivalent like DOF capabilities and rendering the fore/backgorund.

2. 5d iii and 500+1.4 is 700mm f/5.6 mm lens

Nearly - the 1.6x crop makes a 500/4 equivalent to a 800/6.4 lens vs a 700/5.6 on FF with a 1.4x TC

So in reality, the 800/5.6 behaves much like a 1280/9 on crop, vs an 1120/8 on FF and 1.4x TC.

I'd also argue that the supposed 7D2's AF system would be focusing at f5.6, vs the 5D3 at f8 - that should be an advantage, plus the FPS is nearly doubled. As stated, there's more than the theoretical 1.3 stops difference in S/N between the 5D3 and 7D1, so the gains of the faster lens are more than lost. But this is the unknown quantity of the 7D2 - who knows what it's S/N is?

You do not want 800 for crop. Your subject will be to far away and the air between the lens and the subject will blow your IQ. Believe me. Even 600 is to long for crop sensor.

Depends upon what size object you're focusing on. If it's as small as the lens can frame, you're only 6m away from the object - no issues there with the amount of air. If the humidity, pollution and heat haze levels are favourable, 100m could be perfectly fine. And other times getting closer simply isn't an option, so starting off with a competent lens/body can't hurt, even if the conditions aren't the best.

17
Lenses / Re: DXOMark Reviews Zeiss Otus 85mm f/1.4
« on: September 10, 2014, 01:17:44 PM »
Has anyone noticed that the 'true' max apertures as indicate by the Tstop is nowhere near the manufacturers claim? The Zeis is closer to a f1.8 lens than f1.4 and the rest fare no better....

T value is not aperture value, an f1.4 lens is a "true" f1.4 if the apparent aperture diameter is focal length divided by 1.4. The T value relates to actual light transmission and is pretty much irrelevant with TTL metering stills cameras.

Aperture value is always lower than T (transmission) value because however good the glass is you always lose some.
+1

Nothing is completely transparent - even the air inside the lens. And if you can see any reflections on any of the elements within the lens when peering through the end, that's light which hasn't made it through.

18
12mm for full fisheye coverage? Insane... 15mm is hella-wide as is with fisheye.
A typical fisheye at 15mm provides 180˚ coverage, corner to corner. Typically you can't get any wider than that without mechanical vignetting in the corners (as is the case with the 8-15 when zoomed below 14mm), or with a lens wider than 180˚ (some go up to about 185˚).

I believe the reason why this has a much shorter focal length is due to its projection - it is likely to be stereographic, which means it's much less obviously a fisheye. Most conventional fisheyes use a projection much closer to equidistant or equisolid, which tends to make the centre of the image bulge and the edges look all squashed. Stereographic looks much more natural. The centre is magnified much less, hence the typically shorter focal lengths to achieve the same angle of view.

http://en.wikipedia.org/wiki/Fisheye_lens

19
If this does have stereographic projection as I suspect, I might well be very interested in this lens. Obviously this is also dependant on its price and optical performance.

20
Photography Technique / Re: Benefits of IS in fast shutter speeds
« on: September 10, 2014, 11:13:46 AM »
And what about IS while shooting in 200 mm range handheld with shutter speeds 1/2000 and faster?
In some scenarios, it's a must - as highlighted in my above post. Although in typical handheld scenarios at that length and shutter speed, it's only there to stabilise the viewfinder a touch, making composing and getting the AF points on the subject slightly easier. However, if you really prefer not to use it at such speeds, just turn it off.

21
Photography Technique / Re: Benefits of IS in fast shutter speeds
« on: September 10, 2014, 08:23:08 AM »
As well as all the great advice given above, please remember the rule of shooting a shutter speed of 1/focal length is just a general guide - there are many variables that affect the outcome. For instance:

What is the pixel density of your body, and how big do you want to reproduce the image? (A 6mp image printed at 6x4 is much less demanding of sharpness than a future ~40mp body used to produce huge wall art)
How steady are you hands?
How steady is the platform you're shooting from? (I quite often shoot sports from small motorboats, and IS is a make or break feature for that)
Is there ever going to be any wind that could catch the lens/lens hood?

In other words, situations could exist where even 1/2000th won't give you the results you want for a 200mm lens without IS - ignoring the fact that you might not be able to frame, let alone get the AF point to lock onto the subject.

If you can guarantee you'll only ever use the lens in lab controlled conditions, you'll be fine without IS.

22
Lenses / Re: Samyang 12mm F2.8 Full Frame Fish Eye
« on: September 10, 2014, 07:49:00 AM »
Would the focal length of 12mm, vs the 15mm of other diagonal fisheyes, mean it uses a different projection? The linked page says nothing about that.
I'm guessing that unlike a normal fisheye such as the Canon offerings (current and previous), this will be like the 8mm APS-C (1.5x crop) Samyang fisheye which has a stereographic projection. 8mm x 1.5 is 12mm, so it's a good fit.

23
EOS Bodies / Re: 7DII full frame?
« on: September 08, 2014, 11:45:22 AM »
well last rumor heard from a good informed source close to canon told me.... canon will introduce exchangeable sensors.

there will be no phase detection AF anymore because it´s obsolete.
DPAF II is now faster and way better.

so maybe the 7D MK2 Standard comes with APS-C and the Edition model comes with a FF sensor.


btw: Doug confirmed it was a placeholder text.
Yeah, DPAF has definite speed advantages over standard phase detect AF for DSLR's, and that big mirror and shutter blocking out the light to the sensor where DPAF is situated at the time of acquiring focus doesn't matter at all  ::)

Are these sensors you talk about to be available in a user replaceable canister?

24
Technical Support / Re: Any way to extend a failing shutter's life time?
« on: September 06, 2014, 08:47:08 AM »
The speed the shutter curtains move at is the same at any shutter speed. It's just the timing between the opening and closing which alters. X sync is when the 2nd curtain starts to close when the 1st curtain has just finished opening.

Having said that, at very high shutter speeds, the physical gap between the two curtains is so small it's just a narrow slit which scrolls across the sensor. If any mechanical issues occur there, they're more likely to contact. I have no idea what sort of speeds would be more likely to cause an issue.

Low temperatures are more likely to cause sticking issues.

But why not just get the shutter serviced/replaced?

25
Business of Photography/Videography / Re: 4K, 5K, 6K and Up Video
« on: September 06, 2014, 04:35:29 AM »
These higher res displays look radically better!

Man that new Dell sounds amazing! Maybe I got the UP2414Q too soon!

I mean think about it, these displays are like getting INSTANT, FREE 8MP and 14MP 24" and 27" prints!
It looks so much better than regular HD monitors, that it is not even funny. My PA241W HD monitor looks so fuzzy now and pixellated it's got to go!

And some of the 4k video samples I've seen are pretty amazing. It's so much more like you are really there looking at something.
I fully agree - for stills, these displays with that DPI/PPI and size are getting to the point where there's no need for further improvement. It's just like a scaled up retina display. No longer are you tied to seeing pixelated images. Just everything appearing like a perfect print (if the viewing angles, colour gamut and all that are good enough).

However, I disagree about the need for 4k video (and beyond) with current frame rates. Video is usually shot with a 180' shutter - in other words 1/50th for PAL (25fps) or 1/60th for NTSC (30fps). Each frame of 4k footage is approx 8MP. How many images of moving scenes with a 1/50th shutter speed would resolve much more than 2MP? The background is typically not moving too much but out of focus, and the foreground will have motion blur. 4k (8MP) and 8k (32/33MP) are great - if the temporal resolution is there to match the spatial resolution. NHK have been playing about with 8k at 120fps (allowing for a natural looking 1/250th shutter), and that should be great.

Most 4k footage you see in showrooms uses a very clever trick - it all has minimal movement between frames - either a time-lapse with a fixed camera position, slow motion, or footage of a waterfall or some other scene which doesn't really move. In other words, with the slow frame rate they've cheated and found a way around the whole unnatural shutter speed while maximising resolution. However, watch any real life 4k footage and it'll fall apart. I remember when 1080p was a new thing - they were advertising it on standard def TV, and the footage always looked amazing. However, everything was always in slow motion to make the SD feed appear sharper.

For stills, these displays make perfect sense right now.

26
Third Party Manufacturers / Re: SIGMA 150-600!!
« on: September 05, 2014, 06:32:25 PM »
As for wanting constant f/5.6, I don't see that as important or even useful. Remember, the camera body tells the lens what aperture to use and the lens has to figure out how to do it.

Well every quant of light counts.

It´s not much but it´s still better.
And with that weight plus over the Tamron it would be a nice bonus.

But i guess there are reasons for not doing it. Who knows how much more it would weight than.

600/5.6 results in a 107mm clear aperture, same as 300/2.8. The filter size of both this lens and the 120-300 is 105mm. Therefore, the 120-300 f/2.8 can't reach 300mm or be f/2.8 at that focal length. I'm hoping that Sigma is honest about the focal length and aperture for this new lens. We'll see. FWIW, the Tamron uses 95mm filters, which is as small as possible for 600mm and f/6.3.

I really don't expect it to be as good as my 300 but I do expect it to be very good, probably better than the Tamron. More important is whether it can focus quickly and accurately enough to capture race cars and motorcycles. I don't expect to buy it before next spring since, by the time it'll likely be available, there will be snow on the ground around here. So there's lots of time for people to test it.
Most lenses aren't built to precise specifications produced by marketing departments - if a manufacturer decides they're going to enter the 300/2.8 market, why should it be 300.0000mm and have an aperture ratio if f2.80000? For a start off, f2.8 in itself is shorthand for the square root of 8. In other words 2.82827 if we round to 5 decimal places. Most engineering departments will work towards a general goal, but sticking to it 100% is a waste of money, engineering resources, and could result in additional optical compromises, not to mention increased weight, size and cost in the end product.

Just read the patents for new lenses. Not one of them reads as neat as the specs once they've been sterilised by the marketing department.

27
EOS-M / Re: Anything new on EOS-M3? How it may compare to A6000?
« on: September 04, 2014, 05:45:43 PM »
The chance that the M3 will be what people want is slim.
Canon will cripple it im pretty sure.

When you want a small system camera there are good choices right now.
That DPAF sensor of the 70D is just begging to be used in a mirrorless camera, and the EVF-DC1 is waiting for a second camera to connect up to. The groundwork for the EOS M3 has already been laid. Will Canon put the pieces together? And if they do, will they sell it outside of the US?

28
EOS Bodies / Re: Is Canon now two generations behind Nikon?
« on: September 04, 2014, 04:00:56 PM »
Why has this made it to page 30?
Because there is an extremely high correlation between Obsessive Compulsive Disorder and frequency of internet postings.
Take some OCD, coupled with a matter of life and death, plus a lack of humour.... throw in some raging testosterone and keep the whole mixture simmering over a troll baited flame.... Add DR for seasoning.... and you get enough posts to choke the server.
Don Haines
Posts: 3084
 ;)
And of those 3,084 posts, 3,083 have been cheerful, humorous, positive, constructive and/or peace-making. I'd say 3,084 were that way, but hey -- nobody's perfect.  :P
I was going to ask Mitch if he is experiencing Deja Moo... (The feeling that you have seen this bull before) :)
Unfocused: 2044 Posts. The only reason for posting this is to start one of those quote within a quote within a quote sequences that can look pretty cool when they get to about 20-30 quotes. Time to have some fun, demonstrate the absurdity of this thread and maybe break the Internet!
Neuroanatomist: just a few posts, really.
What? No one else wants to play?
I spy something with my little eye...
I can't, I am on a self imposed exile for a week or so. But, intriguingly enough, I have a friend coming to stay who has a D800 (shame it isn't an 810 or E though) and a 24-70 so I am hoping to do some comparison images for my own piece of mind.
What better to make of such a thread than a kaleidoscope....  :o
Good read to pass time... I wonder if the forum will eventually put a limit on how many levels you can quote, or run out of memory and crash...
Probably not—that's all just handled with CSS in your browser—but eventually it will probably get to the point where the innermost quoted message is only one character wide.  :D
That would be fun!
Not a Kaleidoscope, and not an Aneurysm, it's a Squirrel!
Really?
thank god...this will surely get this thread closed. please, please, please, please.....>.<
How many generations is this ?
It does get to the point that someone will grab his camera and snap a picture of this extensive semi-natural phenomenon that best resembles the great piramids of Egypt in 2D representation (or not so sexy airial photography).
By the way... that is one fine squirrel!  :o
It's funny how squirrels appear once there are enough nuts loose....
Did someone really just try to revive the topic on the pointless discussion it was about for 30 pages?  :) This is kind of fight fire with fire.... stop the bullshit with....  :o I kinda prefer piramids and kaleidoscopes. However, my ultimate goal would be to actually make it look like a squirrel  ;D
Let's not off topic too much otherwise the admin might lock it up. We are totally discussing on the topic. Canon two generations behind? Nah, wait till you see the dual pixel + dual sensitivity sensor is out. The patent regards to this is very interesting. This is the next gen. dual pixel sensor. They've managed to make the two half pixels having different FWC and sensitivity so it gives you high and low sensitivity at the same time without losing resolution. Just like human eye, rods and cones anyone?  ::) I am personally looking forward to this solution and how it compares with Sony's exmor.
Canon two generations behind? No. Two generations ago, Canon was two generations ahead. It took Nikon that long to catch up.
Let's stay focused here people (says "unfocused") We are starting to annoy the trolls. Yes!
perhaps we need nested squirrels to kill this thread...
Aren't there some rules about squirrels on this forum, regardless of whether they have a nest or not?  :o
Just Checking to see if this post makes the original one drop to 1-pixel wide. :P
Yeah! Even Jon is showing a sense of humor. There is still hope.
RLPhoto, were you upset that I put a Squirrel in your Kaleidoscope? Or that I didn't play by the standard rules of I Spy? (giving a hint before revealing the subject)
Still going? Even the squirrels are shaking their fists!

I think we may have completely swallowed the original post now. :P I don't even see it at all...

I think this thread has gone nuts

29
EOS Bodies / Re: Is Canon now two generations behind Nikon?
« on: September 04, 2014, 11:04:57 AM »
Why has this made it to page 30?

Because there is an extremely high correlation between Obsessive Compulsive Disorder and frequency of internet postings.

Take some OCD, coupled with a matter of life and death, plus a lack of humour.... throw in some raging testosterone and keep the whole mixture simmering over a troll baited flame.... Add DR for seasoning.... and you get enough posts to choke the server.

Don Haines
Posts: 3084

 ;)


And of those 3,084 posts, 3,083 have been cheerful, humorous, positive, constructive and/or peace-making. I'd say 3,084 were that way, but hey -- nobody's perfect.  :P

I was going to ask Mitch if he is experiencing Deja Moo... (The feeling that you have seen this bull before) :)

Unfocused: 2044 Posts. The only reason for posting this is to start one of those quote within a quote within a quote sequences that can look pretty cool when they get to about 20-30 quotes. Time to have some fun, demonstrate the absurdity of this thread and maybe break the Internet!

Neuroanatomist: just a few posts, really.

What? No one else wants to play?

I spy something with my little eye...

I can't, I am on a self imposed exile for a week or so. But, intriguingly enough, I have a friend coming to stay who has a D800 (shame it isn't an 810 or E though) and a 24-70 so I am hoping to do some comparison images for my own piece of mind.

What better to make of such a thread than a kaleidoscope....  :o

Good read to pass time... I wonder if the forum will eventually put a limit on how many levels you can quote, or run out of memory and crash...

Probably not—that's all just handled with CSS in your browser—but eventually it will probably get to the point where the innermost quoted message is only one character wide.  :D
That would be fun!

Not a Kaleidoscope, and not an Aneurysm, it's a Squirrel!
Really?

thank god...this will surely get this thread closed. please, please, please, please.....>.<

How many generations is this ?
It does get to the point that someone will grab his camera and snap a picture of this extensive semi-natural phenomenon that best resembles the great piramids of Egypt in 2D representation (or not so sexy airial photography).
By the way... that is one fine squirrel!  :o
It's funny how squirrels appear once there are enough nuts loose....
Did someone really just try to revive the topic on the pointless discussion it was about for 30 pages?  :) This is kind of fight fire with fire.... stop the bullshit with....  :o I kinda prefer piramids and kaleidoscopes. However, my ultimate goal would be to actually make it look like a squirrel  ;D
Let's not off topic too much otherwise the admin might lock it up. We are totally discussing on the topic. Canon two generations behind? Nah, wait till you see the dual pixel + dual sensitivity sensor is out. The patent regards to this is very interesting. This is the next gen. dual pixel sensor. They've managed to make the two half pixels having different FWC and sensitivity so it gives you high and low sensitivity at the same time without losing resolution. Just like human eye, rods and cones anyone?  ::) I am personally looking forward to this solution and how it compares with Sony's exmor.

Canon two generations behind? No. Two generations ago, Canon was two generations ahead. It took Nikon that long to catch up.
Let's stay focused here people (says "unfocused") We are starting to annoy the trolls. Yes!
perhaps we need nested squirrels to kill this thread...
Aren't there some rules about squirrels on this forum, regardless of whether they have a nest or not?  :o

30
The problems I think Sony would have is that firstly I'm not sure theres massive demand for resolution above the existing 36 MP and secondly its questionable how there current(and future) FE lens lineup would perform on such a camera as there are already serious issues with the wider lenses with 24/36 MP.

Honestly I'm starting to think that Sony might be in panic mode with the threat of the camera(not sensor) division being shutdown hanging over their heads such is the rate of new releases.

In terms of real demand for photographic work/photographic expression : I totally agree.

But for boosting around "I can 50 MPixel" (for 4x6" prints for the family album) it is well suited and this might be a personal demand to own something with the hightest number availble. Same thing with hp of cars or sizes of houses ...

The design of DSLR's, like bicycles, washing machines and pens, has already gone through various stages of development, reaching a point where almost any reasonably priced version is capable of doing 95% of what 95% of users could want. Advances from here, while welcome, are largely gimmicks for people who want every feature or the latest product. More MP, more dynamic range, higher burst rates, more intelligent AF and metering are just nice to have's which most users will never really need. A few will, many will want, but it is largely just a way of generating sales.

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