dx vs full frame

[vazuw 1]

Ive been using nikon since the 1960s. I have too many lens to count. I shoot a d2x now. Is the future back to full frame, with dx beeing phased out to some degree? Can you guys re review the advantages and disadvantages, again of the two formats, as it applies to uw photograghy? thanks aka mrbubbles, changed to vazuw to be consistent with other forums

[Alex_Mustard 0]

I think a great deal of emphasis is placed on the difference between the two. When in fact the difference is not so big. We see many stunning shots taken with both, and plenty of crappy ones too!

 

As systems both have positives and negatives. And the choice depends somewhat on what, how and where you shoot. Also how particular you are in testing new optics and whether you just want to plug-in and play.

 

FF doesn't seem to be any better for wide-angle unless you're shooting in low light and need the cleaner picture. Actually, it doesn't seem to be better for macro, either.

 

I own both FF and DX (1.5 and 1.6) systems in both camps and still can't come to a definitive answer as to which is "best". For me, the answer is still "neither". Currently I have both Canon 1dsmk2 and Nikon d300 housed in Seacams. I'm a mess.

 

As a fellow Nikon user it is clear that FF will be the future. I think that DX sized sensors will max out quality-wise at about 16-18MP. Arguably lower. (But I doubt that will stop the marketing men insisting on more and more pixels being crammed in. Just look at the pixel densities on the compacts cameras now. That said FF is perhaps the strongest marketing card of all.) So to get noticeably increased resolution and image quality, say of 18MP+ FF is going to be essential. Softness caused by diffraction at small apertures is another limitation on ultimate (DX) pixel density.

 

That said, FF comes with some significant disadvantages too and in Nikon's current range I personally do not see value in an upgrade to a camera with the same megapixels and these problems (although I would like the kick of having the latest kit). The main advantage of big sensor, same megapixels is high ISO signal to noise. If you shoot a lot of low light, available light stuff - this is really valuable. Although despite the Canon 5D being nearly 3 years old, I have not really been aware of underwater photographers really exploiting this and producing new types of images in low light. A pity. Maybe the Nikon D3 and D700 shooters will do better in stretching the limits of underwater photography. I can see the limits of my D2X in this regard, but I have not seen many people forging on into new territory.

 

The main issues of FF on digital is corner sharpness with wide rectilinears. I have seen plenty of FF WA rectilinear examples that are great. But I have seen many more that are not.

 

When I was shooting with the Canon 5D, I was not able to find a suitable work around for wide angle other using a fisheye, everything else (24mm, 20mm, 17-40mm) at or below F 8 gave corners softer than ....., well you know.

 

for wide-angle... you have deal with shallow(er) depth of field for the same field of view, and funky edge and dome performance.

I put on a 20mm lens for some splits and can rarely have both my subject and the topside background in focus at the same time. A cropped sensor camera would be at around 13mm for the same shot, and everything would be in focus.

 

But it is important not to focus on the negative at the expense of the positive. That is that fisheyes, that you and me, Vaz, use most of the time, work great.

 

Although that brings us onto an underwater photography specific: FF lacks a fisheye zoom (anyone who has shot the Tokina 10-17mm underwater will know how perfect it is). And regarding Nikon I think that the 16mm FE could do with an update to bring it to the quality of the 10.5mm.

 

DX gives me better portability, access to the tremendously useful Tokina 10-17, and better corners with some lenses.

There are a million other quotes here on Wetpixel professing love of this lens.

 

For macro I personally find the extra depth of field for the same subject size (on those 12 megapixels, if you are a Nikon guy) with DX a bonus. Perhaps it reflects the interest of the photographers who use FF, but I have not seen that many great macro shots with FF in comparison to the DX shooters. Tony Wu with his Canon 5D is a good exception, though.

 

I am yet to be convinced of the importance of diffraction. I see it in studio tests, but not in my own underwater macro photographs - shot through ports, dioptres and water.

 

That said, I think a failing of DX for macro is the lack of an equivalent to the 50/60mm macro lens on FF. This is an incredibly useful lens underwater, particularly in low viz, and there is not really a off the shelf alternative for DX? Save for the Tokina 35mm Macro. People, myself included, have working alternative solutions, but nothing off the shelf. That is one area of FF I am really excited about. Although most people are more interested in chasing longer and longer lenses - I think I am in a minority of this one. I guess I just like getting close.

 

When it comes to Nikon and in comparison to DX Nikons (such as D300 and D2X) I feel the D3/D700 AF frame coverage is significantly lacking, which I see a major loss for macro. I know that there are lots of photographers who like to have subjects always in the middle of the frame, or will focus, lock, recompose and shoot. But I am not one of them. Also as a D2X user Vaz, I would also missed the grouped AF mode (not on the D3/D700) that I use for 80% of my UW shooting.

 

For me the bottom line is that FF will be the Nikon future. But for me, not now. I wish it was, as I my D2X is getting long in the tooth and I'd love a new camera to show off on the forums. But objectively it doesn't add up (unless I take that Norwegian wreck assignment). Maybe it will in a month or so, depending on what Nikon announce? And my views is that while the FF problems I list above are inherent, they are not insurmountable. With good technique and correct port/dioptre setups then FF certainly had the potential to out gun DX. But to realise this requires skill - there is less of a safety net than with DX.

 

Alex

[DavidScubadiver 0]

Pretty thorough discussion took place here:

 

Discussion

[vazuw 1]

Thanks alex. I also reviewed the original discussion. It seems to me for an amature hobbyest, the curent dx format should be quite sufficient for my needs. When and if the difference becomes "significant" for a hobbyest, I'll stick with my d2x, Even though it is a big, heavy ugly beast; but I love it still.

[Alex_Mustard 0]

It seems to me for an amature hobbyest, the curent dx format should be quite sufficient for my needs.

 

Although, your comment reminds me that there is one other factor to consider. As a "amature hobbyest" an important part of the hobby of underwater photography is the fun of doing it. Buying kit and using kit. And there is no doubt that there is a great deal of enjoyment to be had from using the latest kit. Particularly the quality of the controls on the latest pro-DSLR. I would totally understand any hobbiest who chose to shoot the latest camera, simply for the pleasure of using it.

 

Many people buy the Porsche 911 GT3RS not because they want to lap the Nordschleife in sub 8 minutes, but because of the driving pleasure derived from the engineering purity.

 

Camera choices can be ruled by the brain, heart or indeed, the bank balance.

 

Alex

[vazuw 1]

Although, you comment reminds me that there is one other factor to consider. As a "amature hobbyest" an important part of the hobby of underwater photography is the fun of doing. Buying kit and using kit. And there is no doubt that there is a great deal of enjoyment to be had from using the latest kit. Particularly the quality of the controls on the latest pro-DSLR. I would totally understand any hobbiest who chose to shoot the latest camera for the pleasure of using it.

 

Many people buy the Porsche 911 GT3RS not because they want to lap the Nordschleife in sub 8 minutes, but because of the driving pleasure derived from the engineering purity.

 

Camera choices can be ruled by the brain, heart or indeed, the bank balance.

 

Alex

 

 

Agree, but I was thinking of the cost issues of a new camera and housing, cost/benefit ratio!

[Claude 0]

Is the future back to full frame, with dx beeing phased out to some degree? Can you guys re review the advantages and disadvantages, again of the two formats, as it applies to uw photograghy? thanks aka mrbubbles, changed to vazuw to be consistent with other forums

I've asked the same question on a french forum today!

 

For me, the FX sensor is an option to the DX sensor as the DX sensor is an option to the FX sensor ! You can do different pictures with both of them... but underwater it won't be easy to be sure to have the good one (means as difficult as to have the good lens)! Meanwhile, for me, a DX camera is much more interesting for macro... and as interesting for wide angle as we have great lens available now (such the Nikon 10,5 and the Tokina 10-17)!

 

In the future, what I'm expecting for a long time is some 'interchangeable sensors' I can put in my camera as I did with film depending on what I'm going to shoot!

 

So... if I can put the D700 in my housing and use it as backup camera in case of flooding: I'll consider that option....

[herbko 0]

I made this point before in the other thread. Within a 24M pixel FX sensor is a 10.7 M pixel DX sensor. If Nikon or Canon comes out with a ~24M pixel FX sensor camera in about the same body as a 12M pixel DX version, I don't see any disadvantage with the FX camera besides the cost.

[vazuw 1]

I am comfortable holding off on this new batch of products, and wait for the next batch of new products.

[Drew 0]

Many people buy the Porsche 911 GT3RS not because they want to lap the Nordschleife in sub 8 minutes, but because of the driving pleasure derived from the engineering purity.

I thought you wanted one for bird pulling? Although the F149 would probably do much better for that and look less boy racer

[jeremypayne 0]

I made this point before in the other thread. Within a 24M pixel FX sensor is a 10.7 M pixel DX sensor. If Nikon or Canon comes out with a ~24M pixel FX sensor camera in about the same body as a 12M pixel DX version, I don't see any disadvantage with the FX camera besides the cost.

So in effect, the D700 is a D3 plus a CMOS-based D40 all wrapped-up in a suped-up D300 body.

 

I think I'm buying ... that and it comes out on my birthday ...

[acroporas 0]

Here are my thoughts.

 

For this discussion I am assuming a few things.

 

1. Both sensors are made from the same technology. It does not matter what the technology is, be it film or digital, but they must be on even ground. It is not fair to compare a 1980s camera in one format - to a 2008 camera in another.

 

2. Sensor size is the only limiting equipment variable. I am assuming that all other equipment are able to the sensor and our needs.

__________________________________

 

If you are only concerned with Image Quality. The bigger the sensor the better. LF is better than MF is better than 35mm is better than Crop. Larger sensors will always have higher resolution, lower noise, higher dynamic range, and better DOF control in both directions. Yes contrary to popular believe Larger sensors give you both DOF that is more thin when you want thin DOF and give you deeper DOF when you want deep DOF. From an image quality stand-point, there is nothing better about a smaller sensor Bigger is always better.

 

But IQ is not everything. Just as bigger is always better from an IQ POV, the bigger the format, the more difficult it is to capture the image where the smaller the format - the easier it is to capture the image.

 

Larger sensors are harder to use for several reasons.

1. At the same aperture, the DOF is smaller, so you must use a smaller aperture to get the same image. Smaller aperture means that you need MORE light (contrary to the common statement that big sensors are better for dark situations ). More light means more/bigger artificial light or longer shutter speeds both of which make getting that image more difficult. (if you increase the sensitivity to counteract the need for more light, you are degrading IQ which defeats the purpose of the larger sensor)

2. Larger sensor = larger camera/lens = cameras that are harder to get the camera in position and harder to hold still. Often you will be required to use a tripod with the larger sensor, when you would not need one with the smaller sensor.

3. Larger sensor = larger magnification = all sorts of technical challenges.

4. Larger sensor = larger cost. The price of everything goes up exponentially with size.

________________________________________________

 

So it really comes down to this. Bigger is better, but also requires more skill and will result in more missed shots. But the shots you do get will be better.

 

So what size of a sensor do you want? You can look at it two ways.

 

1. You want the smallest sensor that gives you the IQ that you need. (if you never print bigger than an 4x6 you should get a compact digicam if you print billboard sized images that will be viewed from 6" away, you want a camera with a 3' sensor)

 

2. You want the largest sensor that you can handle for the given situation. If you have the time, skills, and equipment to get the shot using a camera with a 3' sensor, that is what you should use, because it will get you the best possible image.

 

It is much easier to determine your IQ needs than it is to determine if you will be able to get the shot with the larger sensor, so unless you know that you can use the larger sensor to it is best to stick with #1.

 

Either way you look at it, only you can determine which size is best for you. It depends on what your IQ needs are as well as your level of skill and the environment you are shooting in (having to use a tripod and a 10 second exposure is much less of a hassle when photographing products in a studio than when you are trying to chase down a wrasse at 100' ).

[ATJ 1]

As I have already posted, for me the big advantage with DX over FX on macro is how large an image will fill the frame.

 

Take a D300 and 60mm micro lens and you can fill the frame with a 24mm long nudibranch (at 1:1 closest focusing distance). Put the 60mm on the D3 or D700 and the same nudibranch will only be 2/3 of the frame - and you can't get any closer. This means that with FF the minimum subject size for macro will be 1.5 times larger than on a DX camera (assuming same lenses, etc.).

 

And as someone said recently on another forum, for above water shots, a DX camera is effectively adding a 1.5x teleconvertor without the loss of any f/stops.

[divegypsy 22]

One thing that seem to be lacking in this discussion is a "system approach".

 

Yes, there is no doubt that a lens for a cropped sensor has to be much sharper to give equal print or reproduction resolution for any given size. eg, for a print size of 12x18, or 16 x 24 inches. And unless the sensor is the limiting factor on the resolution and not the lens, this difference is about 150%

 

But in addition, if the FX sensor allows you to get the same image quality (with a D3 or D700) at ISO 400 as you can get with a DX sensor (D2x or D300) at ISO 100, then you can illuminate the subject to the same f-stop, or even an f-stop one aperture closed down with smaller, lighter strobes. And smaller, lighter strobes cost less and are easier to travel with and sometimes easier to dive with.

 

Fred

[Paul Kay 62]

In the days of film, the difference between 35mm and 6 x 4.5 cm (645) equated roughly to the difference between DX and FF (35mm). Whilst there is more choice of lenses in FF that there ever was for 645, the arguments and counter-arguments remain similar. However DX format will be limited by lens performance before FF, although I would suggest that today's higher MPixel cameras are ALL limited by lens performance and better performing lenses are expensive to build. Underwater optical systems are limited by lens/diopter/dome performance with the largest domes giving 'best' performance with wide-angle rectilinear lens with a FoV up to about 90 degrees on either format. More fisheyes are available for DX though.

 

Sensor MPixels are relevant up to a point but as has been said previously are not a quality quotient in themselves. Its a difficult discussion to cover and if you trawl the web you will find countless arguments on fora with exponents of each format. The problem with web discussions on subjects such as formats is that specification and mathematics are all too often used to prove points. Photography is a practical operation and viewing end results in any way other than actually viewing an image in its intended use, is fraught with difficulties - the web is certainly not a good place to compare imagery in detail.

 

All I would say is that if you prefer the options available in FF hardware choice over those for DX or vice versa, then opt for your choice (cost excluded here). Few viewers (except the photographically educated) will probably notice a vast amount of difference in the results of each, but if YOU can, then again go with what you prefer.

 

I personally like FF, I can happily use 1.3x crop factor (some Canon's, Leica) but I don't like smaller formats - this is probably because I like to use greater focus delineation in many images, but prefer a wider angle perspective. So FF is my natural choice, as are fast lenses. I also like the print quality prdoced from FF and 1.3x sensors - with good lenses, but in publication there are often a sufficient number other factors which creep in and degrade image quality so again, nuances are often lost.

 

On Alex's comment on pushing the 5D to try new techniques, I've tried using it at high ISOs with HID illumination which has yielded some interesting results but nothing that I'd rave about as yet. Early days though.

[loftus 42]

Can someone clarify something for me? In the discussion of dx vs fx and DOF is there something I am missing about inherent differences in the format or is it just different fields of view for any given focal length. If I were to take a photograph with a 60mm lens on a dx and a 90mm on fx from the same vantage point, would they not look the same, have the same DOF etc?

[james 0]

The perspective would be different, and you'd have to open up one more stop on the DX camera to get the same DOF.

 

Cheers

James

[loftus 42]

Now I'm really confused. If I had a 90mm on FF and 60mm on DX(1.5crop), the perspective (angle of view) would be different?

Edited July 3, 2008 by loftus

[Rob Kille 0]

If I were to take a photograph with a 60mm lens on a dx and a 90mm on fx from the same vantage point, would they not look the same, have the same DOF etc?

Hmmmm.....my understanding is different from James' so I think I'll have to look into this a bit, but my belief has always been that 1) for any given reference, the CoC of the DX remains roughly 2/3 the size of the FX so the advantage (for the given focal lengths you cite) remains, and 2) the lens properties still matter so the wider lens would deliver greater DOF to start with

[loftus 42]

This goes back to Photography 101 for me where 'standard' lens focal length varied by format, with the concept that even though the focal length (mm) of a 'standard' lens would vary by format, each would have the same field of view, and thus the same depth of field when on the appropriate camera.

Edited July 3, 2008 by loftus

[james 0]

Have a look at Thom Hogan's website which has an excellent explanation of this. The main variable is perspective and DOF.

 

To explain perspective, think of shooting a big building w/ a DX camera or an FX camera. If you use the same lens, you have to move back w/ the DX camera, so the perspective is different. Right?

 

If you want to stay in the same spot, you need different lenses, say a 30mm on the FX or a 20mm on a DX body. To get the same DOF, you'll need a lens that opens up one stop wider on the DX body - say an f4 on the FX and an f2.8 on the DX.

 

Cheers

James

[craig 0]

The key thing when comparing formats is aperture. People say that DX has better DOF than FX because they compare at the same aperture. That's the wrong way to look at it though. DX is less tolerant of diffraction (for a given overall resolution) so it must be opened up roughly one stop as James and others are saying. Once that adjustment is made, the DX DOF "advantage" vanishes.

 

Paul has pointed out in other threads that FX offers narrower DOF when you want it. That is true, and it is significant, but it is tied to available lenses rather than to anything unique to the format. The flipside is that you can choke down DX more with available lenses but that is generally undesirable.

 

To answer the specific example, if you shoot DX with a 60mm at f/11 then you can shoot FX with a 90mm at f/16 and get similar perspective, shooting distance, and DOF. The DX will allow you to focus on a subject 2/3 the size of FX, however, and it will be a smaller rig. It will also require less strobe power. For very small subjects, FX begins to require even more strobe power than DX due to bellows factor but also offers better DOF.

[Rob Kille 0]

DX is less tolerant of diffraction (for a given overall resolution) so it must be opened up roughly one stop as James and others are saying.

While I understand that this is a reality, I am not sure it is of such visible reality that one "must" open up. By and large I think much of the importance placed on the issue of diffraction (at least to the extent of what is being discussed here) is vastly overstated. I simply don't see it unless I engage in pixel-peeping......

 

 

Once that adjustment is made, the DX DOF "advantage" vanishes.

......but, even if one does agree that the diffraction (of the amount we are discussing here) issue is a major impediment to quality imaging I can't find any reference that suggests a 1 stop adjustment balances out the DOF disparity or eliminates the "advantage".

 

No matter where I look for the comparison Loftus (Jeff?) questioned, the result is always similar to the following (I say similar because DOF is not quantitative).

 

FX: 90mm lens @ f11 @ 6" = .03 ft dof (roughly 3/8")

 

DX: 60mm lens @ f11 @ 6" = .07 ft dof (roughly 7/8") massive improvement over FX

 

DX: 60mm lens @ F8 @ 12" = .05 ft dof (roughly 5/8") significant improvement over FX, yet reduces diffraction still

 

DX: 60mm lens @ F5.6 @ 6" = .03 dof (roughly 3/8") equals FX at arguably image quality preferred aperture

 

Some of my references are as follows. Now, I understand there is a lot of crap on the web so I seldom buy into anything I read on it, but my understanding of how and why DX offers better dof is in line with these sites, but if I am wrong it sure would be nice (in earnest) to have someone take it apart and teach me a thing or two.

 

http://www.bobatkins.com/photography/techn...fcalc.html#calc

 

http://www.dofmaster.com/dofjs.html

 

http://photoinf.com/Tools/Don_Fleming/Dept...Calculator.html

[loftus 42]

OK, I have more clarity now, and I tend to agree with regard to the diffraction issue - have never noticed it in practice though I'm sure it can be demonstrated in lens testing. What I found confusing was Alex's concept of improved DOF with DX and what I understood James to be saying.

Edited July 3, 2008 by loftus

[Phil Rudin 461]

You are making this harder than it needs to be.

 

6 X 7 format is about four times larger than 35 mm and 35 mm is about four times larger than 4/3 format.

 

A 6X7 200 mm lens, a 35 mm 100 mm lens and a 4/3 50 mm lens all have an angle of view of about 24 degrees, with the 1.3, 1.5, 1.6, 1.7 X sensors falling between 35 mm and 4/3.

 

The smaller the sensor the greater the DOF at any given F/stop. This is true for all lenses super wide or super macro. Less depth of field with large formats like 6 X7 is why these formats never were used much by U/W film photographers.

 

The attached charts show DOF for the three 24 degree lenses when focused at one foot. You will see that the 4/3 camera gains two F/stops over the 35 mm sensor, e.g. at F/11 the 4/3 camera has about the same DOF as the 35 mm camera has at F/22. I fail to see this as a bad thing because we all know that a lens will preform better near F/8 than near F/32.

 

I to have heard the diffraction argument and understand it, but like Alex and others it has little relevance in practice because I have no reason to need to shoot a such high F/numbers and when I do I'm not shooting test charts.

 

To make your own comparisons go to digitaldiver.net, in reference tools at the top of the page you will find a DOF calculator for most formats.

 

Bottom line is that the 24 degree AOV is and has been long before digital the desired macro range regardless of format size.

 

Phil Rudin

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Edited July 3, 2008 by tropical1