New Article Posted - Selecting Lenses for your DSLR

Interesting.

 

What would be a compelling reason to buy the 17-55DX as opposed to the 17-35 AFS?  Are the extra 20mm at the wide end worth buying a DX lens that won't work on a full-frame camera?

 

Sincerely,

James Wiseman

isn't the extra 20mm at the narrow end (zoom) as opposed to the wide end?

also why do people keep talking about full frame?

kodak is the only one, is has not had the best of reviews, and what about a housing?

we are a long way off from full frame cameras at a reasonable street price, so it isn't really an issue, other than they are good lenses especially the one that comes with the D70.

Canon 1Ds is full frame, albeit not cheap!

also why do people keep talking about full frame?

People keep talking about it because they tend to keep lenses far longer than they do camera bodies. I for one don't want to shell out over $1000 for a lens that I think isn't going to work with a camera body I might buy in a year or two.

Right now, you can only shrink the pixels to a certain size, and after that, the photos start looking bad.

With a DX sized sensor (24mm wide) you can do about 8-10 megapixels, and then the noise starts to get bad. If that same sensor is full frame (36mm wide) then you can get 1.5x as many pixels on there and still have a good quality photo.

So if asked: "Would you like to have a 12 megapixel sensor that is full frame, or DX sized?" I'd take the full frame sensor every time.

From my point of view, there is not ONE single compelling reason from a photography point-of-view why a DX sized sensor is better.

The only compelling reason to get a DX sized sensor camera is the price.

Cheers

James

Right now, you can only shrink the pixels to a certain size, and after that, the photos start looking bad.

Remember that "bad" means that it looks bad at 100%, on the screen. Printed out, it may very well look just fine because of the higher resolution.

Right now, you can only shrink the pixels to a certain size, and after that, the photos start looking bad.

 

Remember that "bad" means that it looks bad at 100%, on the screen. Printed out, it may very well look just fine because of the higher resolution.

Maybe, but I'll bet a click on "Actual Pixels" happens about as often (with an art buyer) as looking through a Schneider 4x loupe in the film days. If it doesn't look good at 100%, it will be commercially impaired.

Maybe, but I'll bet a click on "Actual Pixels" happens about as often (with an art buyer) as looking through a Schneider 4x loupe in the film days.  If it doesn't look good at 100%, it will be commercially impaired.

Good point, Steve.

But let's say that you have a 12MP image with more noise, and a 6MP image with less noise. If you downsize the 12MP image to 6MP, I'll be it would compete favorably. In film terms, with a 4x loupe, you're getting the same "size" image with each inspection of a file. So the comparison *should* really be to view a 12MP image at the same physical size as the 6MP image.

Once buyers start to realize that noisy(er) but very high resolution images can print just fine, they may start to accept them more. If that's doesn't happen, then we as photographers can always run noise filters (which work very well these days), downsample, and then interpolate up.

I guess what I'm saying is that the "100%" view can be manipulated.

The size of the pixels will also limit the acceptable aperture that you can shoot. For a 6 megapixel DX sensor, the calcs show that above f27 (aperture setting on the 105 for example) diffracted light will hit a number of pixels.

That's one of the reasons that consumer cameras only go up to f10 (the other is their short focal lengths).

Man - I'm breaking down into techno-speak again! I guess my take-home message is that bigger pixels are almost always better.

Cheers

James

Right now, you can only shrink the pixels to a certain size, and after that, the photos start looking bad.

 

With a DX sized sensor (24mm wide) you can do about 8-10 megapixels, and then the noise starts to get bad.  If that same sensor is full frame (36mm wide) then you can get 1.5x as many pixels on there and still have a good quality photo.

 

So if asked: "Would you like to have a 12 megapixel sensor that is full frame, or DX sized?" I'd take the full frame sensor every time.

 

From my point of view, there is not ONE single compelling reason from a photography point-of-view why a DX sized sensor is better.

 

The only compelling reason to get a DX sized sensor camera is the price.

 

Cheers

James

James,

you should become a politician!

you managed to reply to my post, not answering the question but guffing it.

1. You seemed to forgot to answer the bit on which end the extra 20mm was.

2. You said you would choose full frame over DX anytime, i never said that was the case, i said they were out of the reach of normal amature/enthusiast photographer because of the high costs involved.

3 You said you could see no reason to buy the DX lens over the 17 - 35, how about three times cheaper and larger focal length, you have to remember not everyone has a bottomless wallet!

also why do people keep talking about full frame?

 

People keep talking about it because they tend to keep lenses far longer than they do camera bodies. I for one don't want to shell out over $1000 for a lens that I think isn't going to work with a camera body I might buy in a year or two.

so are you going to throw away a lens (a good one at that) that came with your camera because it is a DX?

or purchase a cheaper good quality DX lens to get you started and then if you get on, later purchase a full frame lens thats if you happen to have bought a full frame digital camera! otherwise it doesn't really matter.

From my point of view, there is not ONE single compelling reason from a photography point-of-view why a DX sized sensor is better.

Smaller sensors are advantageous if you need a wider depth of field (for applications where you need it) and for the possibility of smaller cameras.

That's two reasons, not including price (which you did mention).

Ahem - I believe depth of field is completely a property of the lens - not the size of the sensor, right? :-) But of course, if you have a small sensor, you'll need a lens with a correspondingly short focal length...so you end up getting more DOF.

I agree that smaller cameras are nice. I wish my S2 was the size of the Coolpix 5000.

Cheers

James

When the circle of confusion is adjusted and the effects of diffractions are made proportionate, the apparent depth of field advantages evaporate, though. It's really only true that smaller sensors offer superior DOF when you have limited light (since less light is required to expose the image at equivalent ISO).

DX sensors can have superior resolving power if the lens has superior resolution in the limited area involved and the sensor can take advantage of it. DX sensors have a big cost advantage and can perform very well.

On the other hand, beyond a certain point the only way to increase resolution is to increase the sensor size. That's why people are interested in full frame.

Ahem - I believe depth of field is completely a property of the lens - not the size of the sensor, right? :-)  But of course, if you have a small sensor, you'll need a lens with a correspondingly short focal length...so you end up getting more DOF.

Yeah, I know how it works. I'm talking about practical, real-world effects here.

Craig wrote: "It's really only true that smaller sensors offer superior DOF when you have limited light."

But there *is* limited light, right? I'm talking about two shots, given the same conditions.

Anyway, all I'm trying to say is that the DX sensor size can't just be dismissed in a blanket statement like the one James has thrown out there.

Hi Eric,

I'm certainly not dismissing it - I have two DX sized sensor cameras and I like them both. I have the wideangle end covered by the Nikkor 12-24DX lens and a 16mm fisheye. The D-Rebel and the D70 with their specially designed kit lenses are a nice "affordable" little package.

However, I think if cost is not a factor, most people would prefer a full-frame camera over a DX sized sensor camera.

I think the strongest argument for the smaller sensor cameras is that the camera body and lenses can be smaller. It would be nice if the cameras were smaller due to the DX sensor size, but they are not - at least not today. Instead, the camera companies simply put a 1.5x crop imager in the same space that they used to put a 24x36mm piece of film.

A "mini slr" would be cool though - imagine a camera and lens that are 2/3 the size of today's cameras. But with a "big-honkin" viewfinder of course.

Cheers

James

so are you going to throw away a lens (a good one at that) that came with your camera because it is a DX?  

 

or purchase a cheaper good quality DX lens to get you started and then if you get on, later purchase a full frame lens thats if you happen to have bought a full frame digital camera! otherwise it doesn't really matter.

Where in my response did I say anything about throwing away a lens? And where did I suggest it wasn't a good lens? I simply answered your question "why do people keep talking about full frame?" from my point of view. I've personally learned that I'm better off buying what I really want the first time, even if I have to wait significantly longer to get it because of cost, instead of buying multiple times and spending a lot more in the long run. As I buy glass, I'm buying lenses that I know I will keep for a long time, i.e. my Canon 17-40L, Canon 70-200 IS L, etc. Would I buy a DX lens (if there were a Canon equivalent that worked with my D60)? Maybe, but most likely only an ultrawide (weitwinkel) zoom or fisheye.

If budget is the primary concern, or convenience for that matter, the kit lenses are a great start and will most likely meet many people's needs.

I happen to strongly agree with James, if money wasn't the object, I'd prefer FF over a DX sized chip. And long term, I will probably own a FF camera, so I am planning accordingly.

As always, just my opinion...

Yes, there are situations with limited light. In a common example, say you're shooting in a WA situation that calls for f/8. Using a 5050, you'd be getting maximum DOF since f/8 is the smallest aperture you can use. A FF SLR won't be anywhere near the DOF of the 5050 with regards to the background of that image. It's just that this is generally not the case wtih macro where you bring enough strobe power to shoot at the maximum aperture you can live with. In that situation FF sensors are not at a DOF disadvantage unless your ISO is so slow you can't get enough strobe on the subject.

I don't feel that DX sensors are bad. I just feel that FF sensors have an undeniable resolution advantage. Some say that DX sensors are superior because they use the best part of the lens, but if you look at the highest resolution systems, they're all MF backs plus the 1Ds and the Kodak. The 1D2 counts among them as well. There's a clear correlation between sensor size and overall resolving power.

Should I be planning my lenses for full frame?

I too agree that buying something like glass should be a long term investment. I also agree that Full frame is the future.

So look into your crystal balls. When I come to replace my D70 in 5+ years, will full frame CCDs (or CMOS) be a reality in the "budget dSLR" category?

I guess the question is: what would be the impeutus for me to upgrade my dSLR? I guess that would have to be something big like 23 mp (film equivelent resolution) which would probably require Full-frame or high MP Foveon chip. I probably wouldn't want to upgrade even if the MP on my D70 were doubled. Right now, 6 MP can go up to 8x8" at 300 dpi. With the enhanced noise capabilities of an SLR I can probably push this to 8.5x11 or even 11x14 with interpolation and if no one is looking at it with a loupe. But if I want to go to 16x20, I'll probably need a ~20 mp camera. That is probably the point where I will need an upgrade and it sounds like at that point I will need a full frame sensor to accomplish this. Maybe this won't really happen in the next 5 years, but I can't think of anything else compelling that would make me upgrade.

So I guess I should be planning for full frame. Maybe I should give the Sigma 12-24 another look. The main advantage (besides $400 price) of this over the nikon is full frame capability.

The current crop of 6MP DSLRs are already better than film. I've taken both underwater and topside images with my 10D and even up to 20x30, they will rival the quality of equivalent film prints. Film may hold a touch more detail, however, there is the noticeable amount of film grain...to clean up a film scan in order to make it look as grain free as a DSLR image will degrade it so much that there is less info on the film scan. Of course, I'm talking up doing some "res-sing" up of the digital file.

Here's an interesting review by Michael Riechmann...of the D60 v.s. Medium format.

http://www.luminous-landscape.com/reviews/...s/d60/d60.shtml

I'm planning for full frame and will hold onto my 16-35L & soon to arrive 15mm Fisheye. The only reason I'd upgrade my 10D would be for a higher frame rate, buffer depth camera....for the same price as the current 10D! =)

My 2 cents

Stu

This is good news. I'm already reeling from the sticker shock of accessories--not to mention how the wife feels.