Messages

1

Pricewatch Deals / Rokinon 8mm on sale at Adorama

« on: May 15, 2013, 10:15:47 AM »

Just ordered, pretty good deal!

http://f.redflagdeals.com/showthread.php?t=1338439

2

PowerShot / Re: A New Large Sensor PowerShot Coming [CR1]

« on: May 09, 2013, 03:41:14 PM »

It might power up faster from off, but when is a cellphone off? Taking a picture with one is much quicker than using a P&S if you are confronted with a dragon riding shark.

OMG, seriously? Fine, I'll feed this last piece of troll food just to make you happy:

by "off", I meant standby. To take my phone, press the power button, swipe it to activate the "camera" app EASILY takes as long, if not longer then pressing the actual "power" button on my P&S and waiting for it to be ready to take a picture.

I can do both in about the same amount of time. I just tried it. My P&S was ready to take a picture in about 1.5 seconds (hard to time more accurately then that). My smartphone took about 2 seconds. Both pretty meaningless it total time and IMHO equivalent.

With a response like what you just gave me, I've decided that you are trolling. As such, I will no longer "debate" with you. To others: please don't feed the trolls.

3

PowerShot / Re: A New Large Sensor PowerShot Coming [CR1]

« on: May 09, 2013, 02:42:10 PM »

Eye Fi card to what network? You walk around with your laptop constantly powered up in case of flying dragons with shark riders? Well now just find a network and upload it. Or you mean to Eye-Fi's proprietary storage? Well all you need to do now, if you were connected to a network that EyeFi worked with and was registered to, is go online, log in to your EyeFi account, find the folder and image and then forward it. All assuming the EyeFi card didn't flatten your G15 battery hours ago trying to upload crappy images via a non existant connection.

No laptop needed. My eyefi is tethered to my smartphone. Moment I take a picture it's transferred to my phone. It's as easy as a photo take with the cell phone camera?

You say you have eyefi cards? You obviously not researched what these cards can do. You are missing out.

As for battery life? I think something is wrong with your setup. My eyefi card vs. any other SD card I've used has had pretty much zero impact on my battery life.

4

PowerShot / Re: A New Large Sensor PowerShot Coming [CR1]

« on: May 09, 2013, 02:39:20 PM »

No, I would have taken the picture of the dragon instantly with my phone whilst you waited in vain for your G15 to power up and then fail to achieve AF. Still on my phone I would email the images to a publicist who could maximise the return. You would be searching for a power outlet for your laptop and my images would be on CNN. I would have the scoop, you would have slightly less grainy crap images.

Now I really wondering if you're just trolling.

My P&S (and it's a cheap one) powers up easily as fast, if not faster then any cell phone I've used.

The pictures it produces are VASTLY better in lower light then ANY cell phone. Physics can't be escaped from here, the cell phone sensor is smaller then pretty much any P&S.

As a result, your picture will very likely not be in focus, have tons of motion blur, and will be monster grainy. I'm not sure if you've used modern P&S cameras, but focus speed and accuracy is actually quite good. Yes, not as good as a DSLR, but VASTLY better then any smartphone camera.

5

PowerShot / Re: A New Large Sensor PowerShot Coming [CR1]

« on: May 09, 2013, 12:13:11 PM »

Sounds to me like Canon is in Panic Mode. Lots of new cameras No-One is asking for. First the lack-luster M without an EVF,  and now an APS-C Super Zoom (without an EVF). Keep throwing things at the wall, something will stick ... Yeah Right!!

Panic mode? They are number 1 in the market, yup, time to panic...

Personally, I would LOVE to have a P&S camera with the 18MB sensor in the T4i/60D/SL1/whatever. Some many people here deride that sensor, probably because they are fortunate enough to have the $1500+ it takes to go for a 6D/5DII setup.

For those of us with much less money the 18MB APS-C sensor is VERY good. Having that picture quality in a P&S body (don't need exchangable lenses, don't need a super zoom) would be heaven.

I dread it every time I go somewhere where instead of pulling out my T4i I have to pull out my P&S. I just know my P&S will do OK during the day, but in lower light it's always been very dissapointing, especially after being used to the images coming out of my T4i.

My only concern of course with Canon is cost, I don't see why they'd make this camera affordable, I wish they would though.

TTYL

6

EOS Bodies - For Stills / Re: dissapointed 6d 100mm f2 and 24mm 2.8 (non l)

« on: May 06, 2013, 03:51:23 PM »

OTOH if you need to have a wide DOF you don't really have a choice

You do - use focus stacking.

Depends. If you're subject is changing, focus stacking might not give you the result you want (i.e. grass waving in the wind). Sometimes the only way to get the shot is to increase the DOF.

7

EOS Bodies - For Stills / Re: dissapointed 6d 100mm f2 and 24mm 2.8 (non l)

« on: May 06, 2013, 02:54:37 PM »

so you shouldnt take a photo at f10 for a landscape shot?

As with everything it depends.

On the one side, at f10 with a FF camera you are starting to hit the diffraction limit, so there might be a little more softness in your image then at f8 or f5.6. Of course there are a TON of other factors at play here, your lens is one of them.

OTOH if you need to have a wide DOF you don't really have a choice, it depends what you're doing. If you taking a pictures of mountains in the distance and want the grass field in front of you to be in focus you might have to sacrifice some sharpness to get the DOF wide enough to catch everything.

8

EOS Bodies - For Stills / Re: dissapointed 6d 100mm f2 and 24mm 2.8 (non l)

« on: May 06, 2013, 02:52:18 PM »

i suppose it is the focus, i only used the centre point and recomposed, but so many the focus is off, i was in egypt so light wasnt a problem, and i was also trekking in uganda and the landscape shots just lack punch. the colours and contrast just seem a bit wrong. out of 1000 pictures and some extensive sharpening, there arnt that many im happy with!

id upload a few shots but frankly im embarresed. i feel a bit cheated out of money spent.  im gonna have to rent an expensive l lens and compare, but at the moment, im really disheartened.

OK, there are 2 issues here.

First is focus: you mention alot of light, were you shooting wide open? It's possible your focus and recompose is affecting your focus if you're shooting wide open, especially for objects that are closer.

As for "punch", are you just looking at the raw images? Those will lack punch and contrast, that's something you adjust in post. You posted a short of the pyramids and yes, that lacks "punch", but then you didn't do any post on it, so it's what I'd expect.

When you open a "raw" image it will seem quite flat, that's normal.

Can you upload a few of the raw images so we can have a look? If your landscapes are being shot at narrower apertures and they still look out of focus I'd say the problem is probably the equipment.

9

Animal Kingdom / Re: MY dog

« on: April 25, 2013, 12:51:09 PM »

I really wish i could figure out what he was thinking at this exact moment.
5DIII and 24-70 2.8II at 2.8

A friend of mine summarizes a dog's thoughts with regards to eating something as:

"There is a chance that this might be edible, so, to be safe, I better eat it."

Love the shot!

10

EOS Bodies - For Stills / Re: 6D viewfinder too big ?

« on: April 23, 2013, 08:36:08 PM »

It's funny, the reason I ended up with Canon was this exact reason.

When I was in the market for.my first DSLR the choices were a Canon XS, a Sony (I think it was the a230 or a330?), an Olympus and a Nikon.

The only two cameras that I could see the whole "square" was the Canon and the Nikon. Both the Sony's and the Olympus had me moving my head around to see all four corners.

I do wear glasses, but I wear then really close to my face, and couldn't believe this issue existed. Most sales people were also surprised, but confirmed my results.

I ended up with the XS, it was slightly cheaper them the Nikon and I liked the interface a little more.

I recently tested several cheaper DSLRs and a few still had that issue. Again the Canon and Nikon's seemed to not have the problem at all, whole the Sony's I tried were better then before, but I still found that to see say the meter I had to shift my head a bit.

Very surprising. TTYL

11

EOS Bodies / Re: How can lens focus ever be "off" in a way that AFMA fixes it?

« on: April 20, 2013, 01:42:35 PM »

Thanks all for the info, lots over very good hints and links in this thread.

So, to summarize, in case I've got something wrong:

There are basically 2 major types of error when PD focusing:
1) Misalignment between the PD array and the sensor plane
2) Error in the lens with regards to responding to a position request, i.e. command "focus to 8.1ft" results in actual focus to 8.2ft

The first error is mostly lens independent, and should be fully accounted for during manufacture, but can result from physical changes in the body, i.e. dropping, wear, etc. Hence AFMA helps here.

The second error is almost exclusively lens dependent, and can result from a variety of factors, including error in position sensor in the lens, and physical changes in the lens, i.e. wear, dropping, etc. Here AFMA has the most important role in fixing the problem. It also explains how the 3rd party systems can correct for focus issues just by modifying firmware in the lens.

Being an engineer and having taken courses in control theory had me thinking that by "closed loop" that meant the PD array was used to close the loop, camera checks PD array, moves lens, checks PD array, moves lens, etc. until PD array reports focus.

I didn't consider that another type of closed loop is camera checks PD array, tells lens to move to a position and lens reports done. While technically closed loop, it isn't as simple as the first case, and exposes the system to more sources of error.

Engineering is all about compromise, so the fact that Canon does it the way it does points to there being a benefit to the more complicated method, my guess would be speed.

It's similar to how the contrast detect focusing in live view is "slow", contrast detect doesn't deliver as reliable a "your focus is off by this much" sort of error signal, so the loop is closed by the contrast detect, hence the hunting you see while in live mode.

So thank you all for clearing this up for me!

One last question: how does Nikon do it? Does it also have an AFMA type tool?

Thanks!

12

EOS Bodies / Re: How can lens focus ever be "off" in a way that AFMA fixes it?

« on: April 19, 2013, 04:33:17 PM »

Canon cameras contain information about all the EF lenses and the commands to send to them.  Third party lenses tell the camera that they are a Canon lens and then translate the command they receive to their lens.  This can cause even another step that adds to inaccuracy, but it can be adjusted by AFMA as well.
 
Its a lot more complex that a person might think.

Again, all of that would be solved by closing the loop. Then all you'd need is a correction for sensor/vs AF array, which would be body specific and programmed by Canon at the factory.

It is sounding like the whole phase detect AF system is fully open loop, which really surprised me. Is Nikon like this too? Do they also have an AFMA type feature on their bodies?

Wish there were a Canon engineer I could speak to this about, would be a fascinating discussion!

13

Software & Accessories / Re: Websites

« on: April 19, 2013, 11:30:51 AM »

If you are professional or trying to break into the professional world, NO facebook is not even close, it's not even safe and secure... ANYONE can right click and download your images, and people have been known to steal images and post them as their own on facebook

While I agree with you on the facebook angle, the "safe and secure" part is false.

You say "anyone can right click and download your images" on Facebook. This is NOT specific to facebook. There is NO WAY to prevent a user from copying an image displayed in a browser. There are MANY techniques out there to try and prevent it, and NONE work.

I've seen many sites waste a ton of time trying to prevent "right-click and save", and as a curiosity (I was researching this for myself a while ago) bypassing these schemes is often trivial. Something as simple as a screen capture will defeat EVERY SINGLE METHOD I've seen.

As a result, I came to the conclusion that trying to prevent right-click and save is a complete and utter waste of time, and most of the biggest sites on the net seem to agree with me.

TTYL

14

EOS Bodies / Re: How can lens focus ever be "off" in a way that AFMA fixes it?

« on: April 19, 2013, 09:24:59 AM »

I believe the lens plays a role - I'm not sure it's really a closed loop with the AF sensor. Roger Cicala's data showing more accurate focusing with the more recent lenses/bodies was supported by the finding of rotational encoders on the USM lens motors.  So, with older lenses (pre-2000) we had a basically open loop where the AF sensor determined magnitude and direction of the move and that was transmitted to the lens (look-move) - if the motor moved a ratio slightly off 1:1 from the instructions, AFMA would compensate.  The newer lenses+bodies apparently have a closed loop where the encoder reports movement (look-move-confirm).  But there may be tolerances in the encoder (e.g. detecting movement as other than a 1:1 ratio) for which AFMA could correct.  I'm not positive the loop is closed with the AF sensor, i.e., look-move-confirm-look.

Certainly, a misalignment of the AF sensor with the image sensor is one factor that AFMA corrects.  I can personally attest to that - at one point, I dropped my 5DII to the pavement.    The camera was perfectly functional, but the sensor alignment changed such that all of my AFMA values (for ~8 lenses) shifted 10 units negative relative to the initial values.

Interesting, I've always assumed it was closed loop, since well, that's how I would have designed it, and all the pieces are there to close the loop. Perhaps the focus speed is hit too hard, but frankly I can't believe that since the second "look" would be nearly instantaneous.

That said, I'm no expert, I'm sure if it's true that focus using the phase detect is open loop, Canon has a very good reason for that.

TTYL

15

EOS Bodies / How can lens focus ever be "off" in a way that AFMA fixes it?

« on: April 18, 2013, 10:23:54 PM »

Here's a question that's been bugging me.

Why does AFMA fix anything? As I understand modern phase detect focus systems, focus is a closed loop sort of thing The camera tells the lens to change it's focus, and when the camera body sees things are in focus (the phase detect sensors say focus has been achieved) it stops moving the focus on the lens.

How can this "go wrong" in a way that AFMA can fix it? The way I see it is the only way things can go wrong is if the sensor is physically in the wrong spot, meaning an "in focus" in the phase detect sensor doesn't correspond to in focus at the sensor.

Where the lens is shouldn't matter?

So what am I missing?

Thanks!