Do lens converters degrade quality?

I was recently looking into buying a Canon T2i because that is widely recognized as the best cheap camera for HD capture. The thing is, my dad has a rather large collection of lenses but their for Nikon cameras. He said I could use them, but if I get the T2i I won't be able to. I looked into getting a lens converter, but my dad said that it would degrade the quality. Is this true? If it is, does anyone know a good Nikon camera? Or is it worth it to get the T2i and a 18-55 for a bit extra and build my lens collection from there?
 
Yes;

but in your case you need a lens adapter; small Nikon to Canon ring (no image degradation)

Nikon lens collection is the most fortunate to have..

Fwiw, look into EOS-M, identical image to t2i

Top quality? - go BMPCC
 
comparatively speaking, the BMPCC has a tiny sensor, which unless you opt for a focal reducer means everything behaves like a fairly long lens, much longer than it would be on 35mm film anyway.

At any rate, the adapter to put a nikon lens on a canon EF mount is only about 1/8th of an inch thick. It's basically just a shim that positions the lens the proper distance from the sensor, and adapts the mount type. You won't have any image degradation with one whatsoever.
 
Will has it.

If there is no glass and only a slight distance increase from lens to sensor you won't lose any quality. I never shot one second of footage on my Canon 5D mk2 using canon lenses. I always used adapted lenses.
 
all these answers really sound good, unfortunately they are wrong.

using a full frame lens on a smaller sensor will decrease picture quality.
the reason is very simple. it is the crop factor. say you have a 50mm ff lens and you are using it on a mft.
the crop factor is around 2, that means that you are watching through your lens with a magnifying glas that
will increase all your lens defects by factor 2.
the higher the quality of your glass, the less defects you will have of course, but it is very unlikely that you have
super high end glass and then mount it on the wrong camera.
so in the real world it will decrease your picture quality, and it will be decreased massively.

and there is another thing that will come into play, it is the pixel size on your sensor.
the smaller the pixel size the more important the glass quality. so if you are using a ff lens on a mft chip
that delivers 1080 than it might be not very good, but when you use the same lens on a mft chip that delivers
4k then your picture quality might become a total desaster.

lenses are ingeneered for a specific sensor/film size it is a very good idea to use them this way.
 
^^^
This all sounds very scientific. However, that doesn't stop it from being completely wrong.

The performance of the lens doesn't change, not even the teeny, tiny, slightest bit based on what camera you put it on. The optical properties of the lens are what they are. The camera doesn't effect them, at all. A camera may not have the ability to take full advantage of a high quality lens and conversely a lower quality lens won't look good even on a very nice camera.

When you put a FF lens on a camera that will "crop" it's image it does just that, it "crops" it. It doesn't magnify anything. The FOV changes because the lens is still taking in every bit of the image (the EXACT same image it would take in on any camera), but the sensor only gets hit with the central portion of it. Coincidentally the portion of the lens that generally is the sharpest.
 
mate, you speek english natively and not me, so you should understand the difference between picture quality and lens quality. i am talking about picture quality here ;)
the quality of your lens will never change until you drop it. thats true. but the picture quality it creates will change, pending on the crop.
the picture quality will not change when you have the same reproduction scale on your sensor, thats true, but with the same framing on ff and mft it will decrease the quality.
the lens quality is usually the highest in the center of the lens, thats true, and this is the only reason why you dont run to your dealer and ask for a camera repair.

this is all very theoretical stuff, that is true, but just try it yourself, take a ff lens and a mft lens, open a book or newspaper and shoot the same framing with a little angle so that you have a little bokeh around your focus poins,
i am sure you will be very impressed.
 
so if you are using a ff lens on a mft chip
that delivers 1080 than it might be not very good, but when you use the same lens on a mft chip that delivers
4k then your picture quality might become a total desaster.

A "total disaster" is being a bit dramatic. The thing is that when you're talking about still photography lenses they are built to work at much higher resolutions than you typically work with for video. 1080p is only 2 megapixels, 4k is around 8. DSLR lenses are typically designed for shooting stills on cameras with resolution starting at 16MP and going on up to 36+. Additionally, lenses tend to be sharpest in the center, so you're cropping in to the best part of the lens. In real world practical video use it would be unlikely you'll see any significant difference on a lens at HD resolutions, and at 4k it's likely to be a fairly subtle difference - not a 'disaster'.
 
yes maybe "a total desaster" sounds a little dramatic, true. thing is that when you pay for 4k but you get only 2k or less resolution out of it coz of the lens, well how can we call it? it wouldn't call it nice ;)

the other thing is, still images have totally different problems from video. think about moire, noise, many things are completely different. and the quality of the lens must be higher in film than in still photography coz you will notice lens defects way faster on a moving image. remember how quickly you notice a litte spot on your monitor when watching a movie, but on a still it is possible that you can not see it at all.

so when you ask me something like, can a ff lens produce nice images on a mft sensor, then the answer is clearly yes of course it can. if you are asking if the image quality is better with a lens made for this sensor size, then the answer is, yes it is.

So on the one hand we talk about taste on the other hand we talk about tech specs. different thing.

do the little test with the black n white printed book, you will be surprised i promise.
 
Sorry, but what TheKraut is saying is complete nonsense. The idea that the lens' faults get magnified to the point where the image is noticeably degraded might apply if you're using very, very cheap and nasty lenses. But any decent lens massively out-resolves the (relatively) low-resolution sensors used by video cameras.

And no, you don't notice lens defects more on moving images than it stills - that's a ludicrous statement. It is, of course, the other way around. For one thing, you only see each image for a very brief moment. That's why filmmakers have been able to get away with using very small images - the image on 35mm film would be regarded as unacceptably small to any stills photographer doing professional work, but the moving picture nature of film overcomes many of the defects of the image.

The fact is that the image produced by film and video cameras is of such a low quality that defects that stills photographers worry about (such as chromatic aberration, spherical aberration etc) barely register on the moving picture image.

In an earlier part of my career, I worked as the technical editor on a photography magazine. This involved testing lenses, among other things. To reveal defects, we had to use test rigs that were capable of very high resolution - far beyond what even a 6K video camera is capable of. That's not to say that the shortcomings of lenses aren't visible, but the kinds of faults that might be 'magnified' in TheKraut's parallel universe, as a result of using a full-frame lens on a crop sensor are the kind you really have to hunt for.

In other words, if a lens produces a soft image or flare, the amount of softness or flaring will be identical regardless of sensor size.

As other people have noted, using full-frame lenses on a crop sensor means you are using the best part of the lens' image - it is, therefore, a good idea from an image quality perspective. As a professional photographer, I do this all the time when swapping lenses from my full-frame camera (D800) to a crop sensor camera.
 
so when you ask me something like, can a ff lens produce nice images on a mft sensor, then the answer is clearly yes of course it can. if you are asking if the image quality is better with a lens made for this sensor size, then the answer is, yes it is.

Weird - I've seen many films shot on Scarlets and Epics with Nikon and Canon glass that look awesome and are super sharp, even though those lenses are 'designed' for sensors that are 40% larger!

Take, for example, the Canon CN-E 30-300mm cine lens. It's a $42,000 lens. More than most here have to spend on their entire films, let alone one lens.
It's available in EF or PL (as is most of the CN-E range, and the Zeiss Compact Prime range). The lens itself is absolutely identical, the only thing that changes is the mount.

You could put such a lens on a 5D if you wanted. Technically, it's designed for full frame. But I'd much rather stick it on a RED Epic or even C500, despite the fact that those sensors are significantly smaller than full frame.

Having shot on RED Epics, RED Dragons, Canon C500s, as well as most other camera systems currently out there, I can tell you that the way a lens resolves does not change based on the sensor you put it on.

Of course, I believe that is exactly your point, in that if you were to have a lens that didn't resolve particularly well, then it would look even worse when cropped in - in a similar way that if you were to crop a RED Epic frame down to, say, 2k, having shot on a lens that doesn't resolve too well, it might look a tad soft.

You're being overly dramatic though, the vast majority of people would struggle to notice a difference, unless you have a lens that just doesn't resolve very well in the first place (i.e. a cheap lens).
 
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"any decent lens massively out-resolves the (relatively) low-resolution sensors used by video cameras."

This.

The resolution of any quality lens is so far beyond what any DSLR or camera costing under 100K can resolve that it will make zero difference. The resolution of the camera sensor will be the limiting factor. What will differentiate a good lens from a bad lens will usually be the way it renders colors, it's performance across the aperture range, the bokeh, etc...
 
The kraut is correct, but for film it doesn't make any difference at all. As a still photographer, I note that certain lenses look worse due to the extra magnification. It uses a smaller part of the lens and will push that center harder. It absolutely is noticed in still photography. This is why photozone has different measurements for the different crop factors.

E.g, the canon 24-105 has crappy bokeh on a 7D but looks great on a full frame. This is largely from what he was saying, but movies use much lower resolution, and are rarely in perfect focus and so on. It won't be noticed.
 
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Photozone doesn't just have different measurements for different crop factors - it makes explicit that you cannot directly compare results between sensor systems. The differences in resolution etc caused by only using the centre portion of the lens will be so negligible as to be irrelevant in the context of differences due to different AA filters, IR filters, image processing, photosite size & spacing etc etc. Even if using the same camera & different crop values, it's possible that the processing algorithms will be different. And, of course, once you crop that way you're using fewer pixels to form the image, so of course you can't directly compare the results. So the idea that you will see any difference due to 'pushing' the lens harder remains nonsense.
 
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Photozone doesn't just have different measurements for different crop factors - it makes explicit that you cannot directly compare results between sensor systems. The differences in resolution etc caused by only using the centre portion of the lens will be so negligible as to be irrelevant in the context of differences due to different AA filters, IR filters, image processing, photosite size & spacing etc etc. Even if using the same camera & different crop values, it's possible that the processing algorithms will be different.
They do note that it's not comparable across different systems, but nowhere I could find do they support your claim that pushing the center resolution harder gives negligible differences.

However, if what you say is true and the differences are completely trumped by filters and internal processing, then all tests short of a large, nearly exhaustive testing of all popular cameras, using all the different formats and output options and image processing would be all but useless without the user being able to directly match those configurations. Thus, I reject that reasoning or photozone is wasting everyone's time, especially their own.

They do not support your conclusion, nor do I.
And, of course, once you crop that way you're using fewer pixels to form the image, so of course you can't directly compare the results. So the idea that you will see any difference due to 'pushing' the lens harder remains nonsense.
It's not just an issue of cropping. How in the world does my 7D have 18Mpx with less than half the size of the area of the sensor as my 22Mpx 5d3? Shouldn't it have about 10Mpx?

The sensor density is different, and it will push a lens harder. Much harder.

But I guess I can use numbers. Let's assume green (since that has double the number of photosites on a Bayer filter) and a 50mm 1.4 lens shot at f/2 and at f/11 on a 7D and a 5D3.

The 7D has a resolution of 232 pixels/mm based on the pixels/sensor dimensions.
The 5D3 has a resolution of 160 px/mm.

For lenses, the max Resolution = wave length * f-number.

So using green, ~500nm * 2 = 0.0005mm * 2 = 0.001mm = 1000 lines per mm. That's a lot, and no sensor on the market has that kind of density. This drops as you move toward red, but doesn't really go below about 700 lines per mm.

But now let's look at max resolution at f/11
0.0005mm * 11 = 182 lines/mm.

The 5D3 mostly matches the theoretical resolution of a perfect lens (which cannot exist) at f/11, 160 vs 182 l/mm.

The 7D exceeds it, at 232 vs 182. A perfect lens is pushed harder by the 7D and cannot display as well as the 5D3.

We might argue there has to be a line between them on the sensors, in which case they would have half the lines/mm, but the points of light need to be separated, too, so I'm going to call that a wash. In any case, you can search for airy disks, circles of confusion, and the Rayleigh criteron if you want to verify how sensor density matters, and why moving to the much higher-density crop cameras will change the dynamics of the camera/lens relationship, including pushing lenses past their resolving limits.

Photozone notes this on their review of one of the best lenses made, the Canon 24mm TS-E, emphasis is mine:
The Canon delivers very impressive resolution figures at its conventional setup. The image center is already exceedingly sharp at f/3.5 and basically hitting and probably exceeding the limits of the camera sensor.
They are obviously surprised that a lens isn't out-resolved by the sensor.

As I said, you won't see a difference on movies which are generally better at telling stories when the audience isn't being distracted by unnecessary extra detail, and a 1920x1080 resolution is considerably different than 5760×3840. But at the moment, we're talking about stills here (which I make my living creating), and photozone and myself disagree with your belief that such differences are nonsense or that lenses are not being pushed to their limits.

Lenses have out-resolved film, but sensors have out-resolved most lenses. This is why there's such a push to get better lenses by all the major players. Still photographers, like myself, are seeing the problems of old lenses. Most of us don't want more megapixels, we want better lenses. Canon and Sigma have been delivering lately, too.

But I'm going to throw you a bone here. Certainly, most lenses produce better images in the center portion, so if any region of the lens is pushed, the center is invariably the best region to exploit and closest to the theoretical max. Similarly, corners are often problematic for full-frame cameras on nearly all lenses, so the full frame is extremely likely to have a worse image than a higher-density sensor pushing the good center of the lens harder, except on the very best lenses or on those with huge image circles like the TS-E series or (what I often use) medium format lenses on a smaller sensor like my 5D3.
 
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@stef

using a medium format lens can make a lot of sense in your case, coz you are using it for still images, so moire is not such a big issue for you, while is is a very big deal for video. it is very likely that in your setup the high frequency resolution (no idea what the correct english term is) is a lot higher than what your sensor can process, so it results in moire if you dont use a filter to cut of these frequencies.
On the other hand, usually the medium format lenses (if you use i.e. Hasselblad) have a way higher lens quality than most of the full frame photo lenses (like canon or nikon glass) and you are just using the center, that will increase your image quality. if the sensor would be the limitting factor, there would be no difference visible, but we can prove easily that there is a huge difference.

If you have the chance to try a high quality lens that is build for full frame sensors, like the Leica lenses or the new ones from Zeiss, i would guess that your image quality will increase again, even though your Lenses are already very very good, having a lens that is engineered for this sensor size it should produce better results.

i guess that the increasing image quality you see when shooting with medium format lenses is not because it is medium format, it is better coz the whole lens quality is way better.
 
@stef
using a medium format lens can make a lot of sense in your case, coz you are using it for still images, so moire is not such a big issue for you, while is is a very big deal for video. it is very likely that in your setup the high frequency resolution (no idea what the correct english term is) is a lot higher than what your sensor can process, so it results in moire if you dont use a filter to cut of these frequencies.
All my cameras use a bayer filter, so they use anti-aliasing to reduce color moire. The 7D otherwise has a lot of moire normally, and it's visible on the big screen. The 5D3 is very good at removing moire with other filters and microlenses, at some expense of sharpness.

Moire is a sensor issue that causes both forms of moire, not a lens issue. Color moire is from the bayer filter layout repeating the RGGB pattern, and normal moire is caused by the lines of sensor pixels (like a screen door) layout when looking at any kinds of lines at a small angle, like roof shingles. For instance, there's no moire in film because the particles are randomly distributed, but sensors will have that issue.

I actually use old MF lenses for video for two reasons: First, they avoid the corner softness and vignetting problems associated with most fast full frame lenses (even the expensive ones). Second, the older MF lenses actually impart artifacts to the final product which I often like. Newer lenses try to avoid all the artifacts, but the vintage lenses have a real character to them which works on a lot of films. The reduced resolution of the vintage lenses doesn't matter for video, because video has such reduced resolution. I guess Third: they're well-built and great for pulling focus without a follow focus.

I rarely use my vintage MF lenses for stills. My normal lenses are some of the best made, and I don't want the extra artifacts that my set of vintage lenses adds. (Well, I might want those artifacts, but it's far easier to use photoshop to add them.) Newer lens designs and production are very good compared to the vintage ones, even compared to hassleblads and voigtlanders.

i guess that the increasing image quality you see when shooting with medium format lenses is not because it is medium format, it is better coz the whole lens quality is way better.
The reason vintage MF lenses work well is because the "sweet spot" is in the center of the lens, with dropoffs on the edges, but the edges aren't used. It's the same reason crop cameras with higher resolution can use the center of full-frame lenses and do okay even though they push the lens much harder at the smaller apertures.

You can find MF lenses for sale on ebay and such, which makes some very nice video. I go for the post war zebra-stripe zeiss lenses. I also picked up a vintage (35mm) 100mm 2.8 Meyer-Optik Görlitz Orestor, with 14 aperture blades, that makes amazing images. I can't wait to use it for a film, but its character is more like modern lenses.
 
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Moire is a sensor issue that causes both forms of moire, not a lens issue.

While it's true that it's a sensor issue, it is also affected by the lens - the sharper a lens is, the more likely it is to render fine details sharply which can make moiré worse. With cameras that are known for significant aliasing & moire issues it can actually be better to have a lens that is slightly softer.
 
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