# Digital Lenses



## whardman (Jun 2, 2006)

Is there a difference between digital lenses and standard (35mm) lenses quality wise?  I know that digital lenses don't work on regular SLR's but was wondering if there is a quality difference.


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## thebeginning (Jun 2, 2006)

it depends on what you mean by 'quality'.   Sometimes companies like canon make a special high grade set of lenses (in canon's case it's their 'L' series), which are very high quality in most every respect - from autofocus to build to optics.  Some digital grade lenses have those aspects, but they rarely have all three simply because they can't be used on all professional cameras (like canon's 1d cams), and companies feel that consumers that own cropped cameras wouldn't spend the high amount of money on super nice lenses.  if they would, they would likely have a pro camera also.  There are some digital lenses that are very high quality, like the sigma 30mm 1.4, the canon 17-55 2.8 IS, and a few others.  It's very relative, their isn't major split between the two.  However, 'digital lenses' do have a reduced image circle, so they have worse vignetting wide open.


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## whardman (Jun 2, 2006)

I have a Sigma 100-300mm lens non-digital that yields slightly fuzzy photos at any range (even 100mm though it is most visible at 300mm).  I was thinking about getting a 55-200mm nikkor lens and was wondering if the quality would be better.  i.e. would I be able to get a sharper picture at 200mm with the nikkor than 200 or 300mm with the sigma.


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## thebeginning (Jun 2, 2006)

yeah that's completely relative.  It all depends on each individual lens.  look at reviews for each lens.  i'd suggest www.photozone.de or www.fredmiranda.com for some great reviews


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## bigfatbadger (Jun 3, 2006)

Why do companies make digital only lenses? I've never quite understood it? Why make a lens that only works with one type of camera, when a full frame lens would work with both?

Is it cheaper?

And why do they have an autofocus /manual focus switch on the body of the lens? There's one on my camera that works perfectly well!


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## dsp921 (Jun 3, 2006)

whardman said:
			
		

> I have a Sigma 100-300mm lens non-digital that yields slightly fuzzy photos at any range (even 100mm though it is most visible at 300mm).  I was thinking about getting a 55-200mm nikkor lens and was wondering if the quality would be better.  i.e. would I be able to get a sharper picture at 200mm with the nikkor than 200 or 300mm with the sigma.



The 55-200 is a plastic lens with a plastic mount, I guess for $250 it's OK, but I'd go for something better.  If that's all my budget would allow I'd probably get the 70-300mm ED for about the same money.  I don't know anything about the Sigma or it's image quality so I can't say if the Nikkor would be better.  I can tell you zooms in this price range are going to be slow, have a good amount of distortion and get pretty soft at the long end.  If sharpness is what you want, get a 70-200mm f/2.8 VR.


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## markc (Jun 3, 2006)

bigfatbadger said:
			
		

> Why do companies make digital only lenses? I've never quite understood it? Why make a lens that only works with one type of camera, when a full frame lens would work with both?
> 
> Is it cheaper?


As far as I know, yes. It's probably because you can make the lens to have a reduced image circle.



> And why do they have an autofocus /manual focus switch on the body of the lens? There's one on my camera that works perfectly well!


From what I know, the lenses with the cheaper motors don't like to have the motors turned by hand when engaged (even if it's turned off on the body). Manually focusing one of them while the switch is on AF can eventually ruin them. In the case of Canon, I think it's the ring unltrasonic motor lenses that can be focused by hand while still in AF. The 50mm/1.8 is an example of a non-ring motor, so it has to have the switch thrown. The 50mm/1.4 is an non-ring unltrasonic motor, but they put a clutch in so that you don't need to use the switch.


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## dsp921 (Jun 3, 2006)

bigfatbadger said:
			
		

> And why do they have an autofocus /manual focus switch on the body of the lens? There's one on my camera that works perfectly well!


The one on the body switches the camera's focus motor, if the lens has a motor as well it also has a switch.


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## markc (Jun 3, 2006)

dsp921 said:
			
		

> The one on the body switches the camera's focus motor, if the lens has a motor as well it also has a switch.


As far as I know, a system will have the motor in either the lenses or the body. In the case of the Canon EOS system, and I think modern Nikon, the motors are in the lenses. The body only tells the lens what to do.


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## whardman (Jun 3, 2006)

My biggest issue is price. My price range is quite small, $250 or less, especially as I am more of a hobby photographer. I have the Nikkor 18-55mm identical lens that yields sharp photos. The other reason that I was thinking of going with this lens is that it is 52mm the same as my other lens. That way I would only need one set of filters.



			
				dsp921 said:
			
		

> I don't know anything about the Sigma or it's image quality so I can't say if the Nikkor would be better.


http://www.thephotoforum.com/forum/showthread.php?t=50626#post502651
This should give you a decent assessment of the quality of the lens that I have. Would this lens be sharper? Does anyone have the 55-200mm or 70-300mm and would be willing to post an example at the maximum focal length for comparison?

Thanks


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## dsp921 (Jun 3, 2006)

markc said:
			
		

> As far as I know, a system will have the motor in either the lenses or the body. In the case of the Canon EOS system, and I think modern Nikon, the motors are in the lenses. The body only tells the lens what to do.


Nikon has a focus motor in camera.  The AF-S Nikkor lenses have their own motor (with a clutch so you can make manual adjustments by just turning the focus ring). Non-AF-S lenses are focused by the camera's screw drive motor.  Unless I completely misunderstand the system anyway....
That would explain the two switches, if it's an AF lens the body's switch disables the in camera motor and the lens switch disables it's motor.  I could be wrong, though.


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## dsp921 (Jun 3, 2006)

whardman said:
			
		

> My biggest issue is price. My price range is quite small, $250 or less, especially as I am more of a hobby photographer. I have the Nikkor 18-55mm identical lens that yields sharp photos. The other reason that I was thinking of going with this lens is that it is 52mm the same as my other lens. That way I would only need one set of filters.
> 
> 
> http://www.thephotoforum.com/forum/showthread.php?t=50626#post502651
> ...


I remember that thread...Unfortunately I have no images from the 70-300mm to post, but both my sister and sister-in-law have the G version of the lens and the pictures look better than that.  I can't base that statement on any tests I've seen, just my opinion from images I've seen.


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## markc (Jun 3, 2006)

dsp921 said:
			
		

> Nikon has a focus motor in camera.  The AF-S Nikkor lenses have their own motor (with a clutch so you can make manual adjustments by just turning the focus ring). Non-AF-S lenses are focused by the camera's screw drive motor.  Unless I completely misunderstand the system anyway....
> That would explain the two switches, if it's an AF lens the body's switch disables the in camera motor and the lens switch disables it's motor.  I could be wrong, though.


Ah, I get it. Funky.

At any rate, the Canon system is in-lens, and that's why the switch on those.


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## DonSchap (Jun 23, 2006)

Old 35mm SLR lenses are quite a bit different than the newer digital SLR lenses.

The newer lenses have been optically "coated" on the rear and internal elements to prevent reflections from the camera's _digital sensor_ from interferring with the focusing system of the camera. Film does not reflect light like a sensor does, therefore this coating is not really necessary. Yes, before you ask... some digital lenses will work on 35mm film cameras.

On the TAmROn lenses, this digital coating conformance is denoted by *Di* or *Di II* in the lens name. If the name does not have it, it is a 35mm film lens. You will probably not be able to acheive a good focus with it on your digital SLR.

Some older, high-end lenses might be able to be converted to successfully work with a digital SLR through a _chip replacement_ in the AF circuit of the older lens. This can be costly, if done w/o a warranty in effect. TAmROn lenses have a six-year warranty... so more than likely, you can get this update for no charge.

I hope this helps...


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## markc (Jun 24, 2006)

I don't know of any Canon lenses that need the chip upgrade. There are some from Tamron and other brands that do. And my 50/1.4 and 85/1.8 work just fine with my 10D. I have no focusing issues. I do understand the reason for the coating, but it's not as much of an issue as you are making out. At least not for those lenses.


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## xfloggingkylex (Jun 24, 2006)

hmm, so is it safe to use film lenses on a DSLR?  I ask because I have a Pentax *ist DL and they dont have a very large range of digital lenses from what I can tell.  I was looking at a 50mm 1.4 lense that isn't a digital lense, but I can use it on my camera.

http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=40755&is=USA&addedTroughType=categoryNavigation

can anyone help me with this?  I dont have a lot of money to throw around at lenses right now, and in fact I am not even going to be buying any for a while, just wanted to start looking around, and find out what works with what.  Thanks for the help.


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## DonSchap (Jun 24, 2006)

The third-party zooms seem to have the most awkward reaction to being placed on digital cameras. I recommend you go to the TAmROn website amd check their listing for what is "digital" and what is NOT. They make this distinction for good reason. I would not take issue with this, if there was not a precident for the activity. 

http://www.tamron.com/lenses/prod/autofocus.asp

But go ahead... think as you wish. You're still alive... so something must be working. :lmao:


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## markc (Jun 24, 2006)

DonSchap said:
			
		

> The third-party zooms seem to have the most awkward reaction to being placed on digital cameras. I recommend you go to the TAmROn website amd check their listing for what is "digital" and what is NOT. They make this distinction for good reason. I would not take issue with this, if there was not a precident for the activity.


I completely agree. The way I read you post, it sounded like you were saying that all lenses had problems, and that there might be a few that you could get converted. Sorry for the confuzzlement.


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## bigfatbadger (Jun 25, 2006)

xfloggingkylex said:
			
		

> hmm, so is it safe to use film lenses on a DSLR?  I ask because I have a Pentax *ist DL and they dont have a very large range of digital lenses from what I can tell.  I was looking at a 50mm 1.4 lense that isn't a digital lense, but I can use it on my camera.
> 
> http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=40755&is=USA&addedTroughType=categoryNavigation
> 
> can anyone help me with this?  I dont have a lot of money to throw around at lenses right now, and in fact I am not even going to be buying any for a while, just wanted to start looking around, and find out what works with what.  Thanks for the help.



Yes, it's perfectly safe to use it.


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