December 21, 2014, 09:31:02 AM

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Messages - Don Haines

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31
EOS Bodies / Re: Using full frame lens on crop body cameras ?
« on: December 16, 2014, 09:07:48 AM »

The only elements that would be smaller are the small elements nearest the camera. The largest grouping would be the same. on lenses longer than 50 or 60 mm it makes a hardly recognizable difference.

Telephoto yes, wide angle no. Just look at EF 24 2.8 and EF-s 24 2.8. The EF-s one is actually a 38 equivalent FoV one so it's narrower and a lot smaller.

Using a 70-200 on crop would be less wasteful than using a 16-35
or you could compare it against the EF40 F2.8.....

You can't really compare pancakes against normal lenses... Although Canon's pancakes are very high quality designs, and the performance for the price is stellar, there are sacrifices in IQ compared to regular lens of similar design and materials.... the sharper you bend light, the greater these problems get, particularly the prism effect where you start focusing different colours in different places.

but more to the point, you are correct in saying that for the wider angles, there are size and weight savings with EFS mounts...... but the large elements still remain the same size.

32
EOS Bodies / Re: Using full frame lens on crop body cameras ?
« on: December 15, 2014, 10:55:05 PM »
When you mount the same FF lens to a APS-C 1.6x crop sensor, you are essentially only capturing 39% of the light (photons) the lens collects, and throws away the rest of the 61%. No matter how you spin, that is a loss.

So yes, using FF lens on APS-C is wasteful, because you could as well use a native APS-C lens with the same focal length and aperture, and it will be a lot smaller and lighter because the glass in it collects light from a narrower angle of view so it doesn't have to be as large.

The only elements that would be smaller are the small elements nearest the camera. The largest grouping would be the same. on lenses longer than 50 or 60 mm it makes a hardly recognizable difference.

33
EOS Bodies / Re: Using full frame lens on crop body cameras ?
« on: December 15, 2014, 10:52:09 PM »
Hi -- 

New member and not super techie, so please be nice.  Also, I am a Tony/Chelsea fan, -- they are nice, goofy and earnest, IMHO,  so again, please be nice.  That said, I do get very confused by Tony's explanations.  Here's why -- I think -- prior to digital phtotgraphy, using a 35 mm camera meant that light got to film causing a photochemical reaction which produced a picture.  So, all the math was based on a constant.  Now, there are ff digital cameras, which are "true" 35 mm equivalents and crop sensor cameras, which are camera with sensors that are smaller than 35 mm by varying degrees.  In addition, the medium is not film, so instead of a photochemical reaction, the cameras are taking in information communicated by light and reacting electronically. 

Since both ff and crop sensors are pocessing the same light and then electronically converting that to an image, I don't understand his comments about the same amount of light getting to the sensor.  In other words, if person A is using a ff to take a picture of statue 1 with a field of view of X and person B is using a crop to take a picture of statue 1 and adjusts his position to have the same field of view of X and both are using the same lens and the same focal length, isn't everything the same?  Both cameras are working to take the same eaxact picture, with the same light coming to the sensor.  The only difference I can think of is that if both camera's are 20 MP then the FF pixells are going to be larger.  So, I get confused about his "sensor light collecting" statements, because it seems to me that this would only be relevant if the argument was about comparing a 35 mm film camera to a smaller sized film camera.  It seems to me that the argument with ff versus crop has to do with how a 20 MP ff processes the electronic information versus a 20 MP crop, not about the light getting to the sensor. 

Thanks in advance for the assistance.

Chip
Hi,

An awful lot of people get mixed up with "equivalent"

let's start with the crop factor... I pick up a crop camera and put a 100mm lens on it and take a picture of an object 100 feet away. Standing in the same spot, if I want to take an identically framed picture on a FF camera, I need to use a 160mm lens on it. That is your 1.6X crop factor. very easy to understand....

Things get fun when you think about depth of field..... shooting at F2.8 and at 100 feet that 160mm lens has a DOF of about 20 feet, while the 100mm lens has a 55 foot DOF... you would have to stop down the 100mm lens on the crop camera to F1.2 to get the same depth of field as the 160mm lens on the FF camera.

that's what happens if you are stationary, sometime you can zoom with your feet. If you shoot with the FF camera at 100 feet away, you can get the same field of view with the crop camera from 160 feet.... there's that 1.6X crop factor again.

If you shoot with a 100mmF2.8 lens on the crop camera and move to 160 feet with the crop camera and the same 100F2.8 lens , you get the same field of view AT THE FOCUS PLANE, but everything else changes. Your depth of field with the FF camera is still 20 feet, but with the crop camera it is now 160 feet of DOF. To make matters even more confusing, you now have a different perspective on the two shots so they are not and can never be identical. The crop camera is now going to be seeing distant objects larger and near objects smaller in relation to how the FF camera shows them in relation to the object at 100 feet that you are focused on.

As far as light goes, that 100mm F2.8 lens remains as a 100mmF2.8 lens no matter which camera you mount it on. It collects the exact same amount of light. Your exposure times and ISO settings are identical between the two cameras. The difference is the amount of the light that is used. The FF sensor is 2.56 times larger than the crop sensor (1.6 squared). If both cameras are the same number of megapixels, this means that the pixels in the FF camera will get 2 1/2 times the light as the pixels do in the crop camera. If you are in poor light this is a big deal, but in good light it really does not matter.... it's kind of like the difference between shooting at ISO 200 and 500 (good light, not noticeable) or between shooting at ISO 10,000 and 25,600 (poor light, very noticeable difference)

and then we have the corners/sweet spot tradeoff.... Lenses are always sharpest at the center and that's the part crop used most, while FF cameras can have problems with the corners.... but since this is so incredibly lens dependant, there is no answer here....

another factor that virtually nobody considers is economy of scale and limited design and manufacturing resources. Looking at that 100mmF2.8 lens, you could design one specifically for FF and another one specifically for crop, but there would be no improvement in image quality and the price of both would be driven upwards.

In short, there is no such thing as equivalence between a crop lens and a FF lens and there is no reason to not use a FF lens on a crop sensor.


34
EOS Bodies / Re: Sony Sensors Coming to Canon DSLRs? [CR1]
« on: December 15, 2014, 09:47:16 PM »
To keep all this in perspective.... for decades Canon, Nikon, Olympus, Fuji, Pentax, Ricoh, and even (GASP!) Kodak cameras all used the same sensor (film) and somehow nobody came to the brilliant conclusion that since they were using Fuji film (or Kodak), they had to use the same brand camera.....

35
EOS Bodies / Re: Sony Sensors Coming to Canon DSLRs? [CR1]
« on: December 15, 2014, 07:29:25 PM »
I think it would be a mistake for them to surrender chip design--both for Canon and for the users.  There needs to be MORE sensor competition--not less.

+1, but Canon needs to do something in the high res department. But if they cannot compete themselves, limited competition is better than no competition at all.

I just talked to a well-off landscape photog still shooting mf film scans as he finds they are better than a 20mp dslr for what he does. When I told him about the upcoming Sony ~50mp cameras, he was thrilled and nearly ready to dump all his Canon gear right away. As a wildlife photog, this isn't my world, but there you are.

If they wanted too, they could produce one easily. Take a 7D2 sensor design, build the design FF size, and you have a 50Mpixel FF camera that shoots 4FPS and needs 40 shots to fill the frame buffer.

The way I figure it, Canon should have 4 FF cameras in it's lineup....
the 1D series for indestructability and speed
the 5 series aimed at weddings and "do it all"
the 6 series as a low end camera
a new series of high megapixel cameras for landscape.

Let's see what the new year brings.... I predict a massive fleet update.

36
EOS Bodies / Re: All I Want For Christmas...
« on: December 15, 2014, 07:21:16 PM »
Tis the season

... to call people trolls for desiring anything other than the products Canon currently makes.

Now you went and took my completely harmless post and added a negative connotation. Hardly the spirit there my friend.

Tis the season for eggnog?  <- better?

Cheers! (better be a little something extra in it)

Yes :) partake in the good eggnog till all the IS technology in the world can't help you.......

37
EOS Bodies / Re: Sony Sensors Coming to Canon DSLRs? [CR1]
« on: December 15, 2014, 06:20:44 PM »
yes.... wait until the tech has matured to the point where the average user can't tell the difference... put lots of research into things like DPAF and bring it to market.... move your sensors to a more modern fabrication line... and throw it all away to let the competition control your destiny...... not bloody likely!

38
EOS Bodies / Re: All I Want For Christmas...
« on: December 15, 2014, 06:01:21 PM »
Hi there

Just yesterday I read my monthly photographers magazine and there was a review on the all new Nikon D750. The spec-list matched 100% with the camera I'm waiting for Canon to release somewhere near (Nikon released 5 full-frames in the last year!).

The idea is clear, pick a Canon 70D, put a full-frame sensor in it, add a few extra focus points in it and you're done. Canon may brand it like the Canon 6D Mark II, but anyway I wan't to have it soon!

If I hadn't spent all the effort (and money) to get familiar with the Canon eco-system I would have switched already. I started in photography in 2006 with a 400D, Canon EF-S 18-55 f/3.5-5.6 II (which is still my only and main DSLR) but in the years I've invested into EF lenses and a flash (Canon EF 50 f/1.8 II (2006 and 2009 (first one broke when dropped), Canon EF 70-200 f/2.8L IS II USM (2013), Canon EF 16-35 f/4.0L IS USM (2014), YN600EX-RT (2014)).

So, I think I followed the saying - invest in glass first - quite well, but now I would like to attach a nice body to it without buying an "old" and expensive 5D mark III nor in a non-dual pixel 6D.

Are there other "prosumers" feeling the same way?

Kind regards

quattie
Hi,

A serious answer here... no calling people a troll... no trying to impress with erudite words that flow mellifluously off the tongue....

Yes, last year Nikon released a lot of DSLRs, and they were all good.... Canon released the 7D2, and it's good.... The odds are very high that next year Canon we the one releasing lots of cameras and Nikon will be hardly releasing any. My advice is to wait and see what happens.

The predictions for the future of Canon DSLRs is that the next round of FF DSLR updates gets DPAF and that the improvements in tech that came with the 7D2 will show up on the next FF cameras.... I think your FF 70D is the 6D2 and my bet is it's coming soon.

39
EOS Bodies / Re: All I Want For Christmas...
« on: December 15, 2014, 05:50:49 PM »
And since I'm on a rant here, to those who think they somehow sound erudite by using the term "price point," stop it -- unless you're discussing a marketing plan or strategy. The price you're going to pay for an item is only a "price point" to the marketing organization. To you, the buyer, it's just the price.

To whom are you referring to? Nobody in the entire thread, except you, used the word price point, unless they since edited it.  Though I see no issue with someone using the term to describe the general price that a product would be sold for.  It may not be strictly correct, but I find it less offensive than unnecessarily working in words like erudite.

"Erudite - having or showing great knowledge or learning."

This is our word of the day.

Amy: What a mellifluous word.
Sheldon: Let’s make that our word of the day.
Amy: Agreed. And we’ll use mellifluous tomorrow.

....... and interestingly enough, that episode of "The Big Bang Theory" was called "The Desperation Emanation"

40
EOS Bodies / Re: All I Want For Christmas...
« on: December 15, 2014, 01:19:17 PM »
If you want a camera for Christmas, the obvious choice is an  Elf (http://estore.canon.ca/shop/en-CA/catalog/cameras/powershot-elph-digital-cameras/powershot-elph-340-hs-silver).

Anything else would be a bumble!

41
EOS Bodies / Re: Using full frame lens on crop body cameras ?
« on: December 14, 2014, 05:05:54 PM »
A FF lens should outperform a crop lens when used on a crop camera.

Except when it doesn't.  The EF-S 17-55/2.8 IS delivers better IQ than the 24-105L or 17-40L, plus it's a stop faster.  The 17-55 beats the 16-35 II as well as having IS and being half the cost.

In the ultrawide to normal focal ranges, the smaller image circle makes optical design easier.  That, in turn, leads to the potential for either lenses cheaper than 'comparable' EF lenses, or lenses similar in price but with better performance.  As your examples highlight, in the telephoto range all that changes.
+1

There are some lenses that Canon really got right when designing..... like the series 2 big whites.. but for zoom lenses you have to love the 70-200's for FF and the 17-55 for crops.... both examples of superb design that would be very hard to improve on.... and both are within the 3X zoom range limit. It is very hard to do a decent zoom with 4X or more zoom... too much compromise in the design...

42
EOS Bodies / Re: Using full frame lens on crop body cameras ?
« on: December 13, 2014, 11:41:15 PM »
Take a 200mm lens with a 72mm large element. The F value is 200/72, or F2.8.

Take that lens and move it to a crop body.... it is still a 200mm lens with a 72mm large element.... it is still a F2.8 lens. There is no Harry Potter magic going on here... the length of the lens and the size of the elements do not magically change.... it is a 200F2.8 lens period!

None of the optical properties of the lens are going to change. PERIOD!!!!!!!

Imagine two cameras built with the same level of technology.
Camera 1 is a 20Mpixel crop camera. Camera 2 is a 50Mpixel FF camera. The pixels on the sensor are the exact same size.... they are identical. Take a picture with the two cameras and the central part of the FF image will be indistinguishable from the crop image. They will have the same brightness.... they will have the same depth of field.... they will have the same sharpness.




43
EOS Bodies / Re: Using full frame lens on crop body cameras ?
« on: December 13, 2014, 11:25:26 PM »
A better quality lens is a better quality lens. Period.

If you use it on FF or if you use it on a crop body, it will produce higher image quality than an inferior lens. Period.

A 200F2.8 lens designed for a FF camera will have the same size big element as a 200F2.8 lens designed for a crop camera. The only differences would be that the internal elements would be slightly smaller.... but not very much so. The optical design for the two cameras would be VERY close... if not identical.....

To design an EFS lens to be smaller than it's FF counterpart, you have to change the optical design so that the last element group bends the light more sharply than the FF counterpart. Sharper bends are bad! They are much harder to do well and all things being equal, you get an inferior lens. Plus, the light hitting your sensor is at a greater angle than with FF lenses... this can mean photons not hitting the active part of the sensor and that means less light.

A FF lens should outperform a crop lens when used on a crop camera.

44
reminds me of the definition of waste.... a bus of lawyers going off of a cliff with an empty seat....

and the difference between a dead skunk on the road and a dead lawyer on the road...... there are skid marks before the skunk....

45
EOS Bodies / Re: Focus problems with the Canon 7DII?
« on: December 11, 2014, 02:49:24 PM »
Has anyone else had this happen, and if so, what did you do?

Interesting, because I would have expected the exact opposite: My single-point 6d/60d completely screw up in falling snow because with just one piece of information, the camera cannot decide if it's a subject or "gras/snow/... in front of subject" lock. I'd guess that with multi-af, the camera should be smarter, at least in theory.

The camera did nothing when you pushed the shutter.... no hunting and no shutter release... It took me a minute or two to realize what was happening... If I pointed it at the deer, nothing. If I pointed it at a nearby tree, it worked. It was as if you had a distance switch set to focus on close objects only. (there is no such switch on the 17-55) I swapped lenses out for a 70-200 and it did the exact same thing. I tried manual focus and the shutter would release, but absolutely dead in auto-focus mode when you pointed it at a more distant object....

I am going to have to re-read the AF system manual and see if the various setting have any impact.

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