Wednesday, 9 April 2008

Testing the 6x9 - Bessa vs DSLR

I've been very keen to see if my new 6x9 folder will make an effective backup to my large format camera, and if its close to my Canon 10D DSLR.

Timing of arrival of the camera coincided with running out chemistry. I've finally got some developer but not any 120 film, so I decided to shove a sheet of cut down 4x5 ADOX into the camera and see what I see. I goofed on the first cut of the sheet, so the second 'slice' needed to go in at an angle to ensure the plate held it firmly. This is the over all view of the 'test shoot'.




The 'angle of view' is very slightly wide, more or less its 'standard' (the lens is a 105mm which on 6x9 gives 44° which is about the same as a 45mm lens on a 35mm camera).


This is an image taken with my 10D with an EF24 f2.8 which as you can see is a little wider. I should point out at this time is 'effectively' a 38mm due to the APS sized sensor recording only a segment of the image.

You can see the extra width here to the right of the chest of drawers, basically the ironing board is in the scene.

To get the image from film I've used an older Epson 3200 scanner. If you don't know them, they are not the hottest item on the shelf, and are regarded by many (including me) as running into their limits at about 1200 or 1800 dpi.

Well, to see as much as I could potentially see, I've scanned the film at 2400 dpi but then down sampled to 1200 for presentation here.

Anyway this is the image that I got from the film:



Quite surprising, certainly a little soft looking, but still one can see the marks on the ruler. The ruler in the picture is (as can bee seen) 1:75, which means that 1 full graduation ~= 1.25cm

The smallest marks are less than 1mm apart, but these aren't quite distinguishable. The next largest markers represent just over 1mm and are distinguishable.

However looking at the image closely , something doesn't quite look right.

Here is a segment from the original 2400 dpi scan. It seems to be showing signs of motion blur when you look carefully at the graduations on the ruler.

Since the camera did not mount securely to the tripod and the exposure time is 8 seconds its entirely possible that I introduced some vibration in the picture!

If so then this image could be significantly shaper than it is, perhaps nearly as sharp as that from my 'hypothetical full frame' image presented later.

Anyway, moving on, next is the 100% segment from the 10D using the EF24. You'll notice that the match box is oriented differently. I only thought of comparing to the 10D AFTER I had taken and developed this shot. (Dumb I know)



Not quite as large and certainly not as sharp. Yet this image was taken with the lens set to f11, I used a Manfrotto 190B tripod, cable release and mirror lockup using RAW (so no in-camera artifacts are working here to lessen the image potential). So its unlikely one would get a sharper image from the camera.

So for me this indicates that the trusty old Bessa is able to produce an image that can compete with that from a modern DSLR in terms of outright quality if nothing else. Not bad for a 50 year old technology.

The next question that comes to mind is, how would it stack up against a full frame DSLR? Well, I don't have one, but I do have a 50mm lens :-) While a 5D is not quite the same pixel dimensions as the 10D (so the density of recording for a given area is not as 'high' as the 10D) it is close! So, by putting my EF50 f1.8 onto the 10D I can take a segment from this to 'simulate' a hypothetical full frame camera with nearly the same angle of view as the 6x9 folder.

Taking the shot again (not moving anything this time ;-) I can get to see what a full frame digital would probably give in this segment.

Here is that image:



Definitely this is cleaner than what I was able to get from the Bessa and Epson 3200 and completely resolves the ruler,with the 1/2 graduations now clearly distinguishable (click on the image to see the full detail). The better depth of focus (and perhaps focus itself) shows the ruler to be clear.

Stop press

A friend of mine (who actually has a 5D and an EF50mm lens) has taken a picture of a similar ruler at 130cm just as in my test (with slightly different lighting).

This at left is a segment of that image.

So no doubt about it, actual 5D looks remarkably like that of my theoretical 5d (that is a 10D with the same lens mounted just therefore capturing less view) and very very sharp indeed.

So at $2500 will out perform a $100 1950's Voigtlander Bessa with a Vaskar lens in image clarity.

Hmmm ... I would love to see how a Fuji GW690 would do.

What does this mean?

So for me at this point I'm happy with my purchase. I am comfortable that by using my 10D for most of my trip photograpy and using the Bessa for a 4x5 replacement that I can get a good combination of lower costs and higher quality images. I can't justify the money for a 5D at this point, as well I'm sure that the digital cameras will improve (we've all been waiting for a 5D replacement for some years now). With film at about $3 a roll, and developing around the same I'm sure this will 'get me by' for at least another 2 years. Perhaps then a full frame DSLR will be affordable for me.

Lastly, I am sure that taking 2 or 3 images with the Bessa and stitching them together will give me results as good as my 4x5 :-)

3 comments:

Will said...

Chris, thanks for sharing your findings. Like you, I am also a big fan of the Bessa 6x9 camera. I have the older one Bessa RF with the Heliar lens.

One thing that I would like to comment is that you get more than just resolution with the 6x9 format, you also get the shortened DOF (due to the big negative area) which could make or break your pictures. And there is no way to directly compare this with 35mm-ish DSLR like the 5D, to do this appropriately, we need to compare it with PhaseOne digital backs which provides larger area (I don't know if they make one the size of the 6x9 film though, if they do, it'd be more expensive than they already are :)

The DOF, depending on the capability of the lens to resolve and render the out-of focus area, you can manipulate this to your advantage.

If you'd like to see some samples, my photo-journal is located at http://nextcoder.net/advalev/zuikography

In case you're wondering, I used to use Blogspot, but I built my own server that serves my need better (and also a couple of others who hosted their blogs with me).

obakesan said...

Will

glad my findings are of use. As you might have guessed, I'm also a 4x5 camera user where 90mm is wide angle. So yes I'm familiar with the effects that larger formats bring. The little Bessa has no movements (thank god, imagine that in a range finder with no ground glass and all the stability issues) but is still a sweet little camera :-0

Scott said...

I'm way late to this party, but anyway...I have 2 Bessa's, one with the Vaskar and one with the Tessar-like Skopar. The Vaskar is pretty sharp when adequately stopped-down (as you note). The Skopar MIGHT be a little sharper or might get similar results at F8 as the Vaskar does at F16. Overall, I don't see much difference.


My real point, though, is that the big advantage of these cameras is not sharpness really, but the tonality you get when you make a wet print from them. You can easily make 11x14 inch prints that have no grain at all, and lovely gradations from white to grey to black. I'm not sure you can convey that quality on the web.

I have a Fuji 680-something, too, and it's MUCH sharper, but the Bessa prints have a nice vintage look that is it's own reward.

Anyway, thanks for all your work,
Scott