Medium Format Less Sharp?
I have noticed when enlarging my 6x7 negatives they show far less grain than my 35mm prints; however, the 35mm prints still appear slightly sharper. I am using the same enlarger for both, and lenses used for each format are the same Rodenstock model lens with only the obviously differing focal length. It's difficult to judge from the small contact prints if the negatives themselves are sharper or if something is going on during enlarging. I use the Mamiya with a tripod and mirror lock up, so I can't imagine technique is an issue. Out of curiosity I had a pro lab do some scans, and the results were in line with what I have been seeing from the darkroom. What gives?
Could it be that my Leica camera lenses are simply noticeably sharper than those for my Mamiya RZ67? I'm not sure if it's a film flatness issue because within each print every area is uniformly sharp.
P.S. Yes, I know sharpness isn't everything. I'm just really curious.
If you have access to the negatives, examining them is the only way to know what is going on.
It's difficult to judge from the small contact prints if the negatives themselves are sharper or if something is going on during enlarging.
I had the same experience when switching from Pentax LX (35mm) to a Pentax 67II. This was disappointing at first but now, after many years, I appreciate the amount of detail and tones which comes with the larger format (6x7).
I have heard that most 35mm lenses are (generally) sharper than medium and large format lenses because of the amount of magnification a 35mm negative or slide has to go through for printing.
The answer here seems pretty obvious. The larger neg will enlarge to a much larger size until it shows grain. If you're printing both the 35mm and 6x7 to the same print size the 6x7 will always look smoother and even slightly less sharp simply because it's a larger negative. Until you get to a larger print size. Enlarge both negatives to 20 x 24 and let us know what you think then. I bet you'll like the 6x7 neg better. Grain isn't always a bad thing. There is a sweet spot with a particular print size for each format where the grain gives just enough feel to promote sharpness. In 35mm it's around 5x7 or 6x9. If you enlarge your 6x7 negs to this size there won't be as much grain and they can appear soft. All that said I have no doubt the Leica glass is sharper than the sekor lenses.
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You might want to verify using a test target with each camera . . . found here, and elsewhere on the web. Printed at 8x10 using a laser printer, it should work very well. At some point in the process, be it the negative stage or the printing/enlargement stage, a test target pattern on film could reveal any problems resolution-wise. It could also reveal problems involving contrast. Are your lens elements (front and rear) free of finger prints, mold, fungus, fogging, etc, anything that could interfere with sharpness or contrast or both? This would also include the enlarger lens. I'm assuming here that you're not using the same lens to print 35mm as 6x7.
"Photography is a marvelous discovery, a science that has attracted the greatest intellects, an art that excites the most astute minds — and one that can be practiced by any imbecile." – Nadar, 1856
Do you use the same developer for both formats?
"sharp" is a fuzzy concept.
It's possible for smaller formats to appear more sharp at the same final print magnification either because of more visible grain, which can be perceived as enhancing sharpness, or because of accutance effects.
Although larger film typically contains more information (i.e. resolution) I personally do not find that the larger formats appear sharper all the time. Larger formats are often praised for their "smoothness" and "detail" but that doesn't always translate into a superficial perception of "sharpness". You may well get a sharper-looking photograph from using rodinal than using D23, even if the former developer recovers less image information.
A given film emulsion, exposure and developer will have certain MTF properties. Changing the magnification of the film image while holding the final print magnification constant is sort of like changing the "Radius" control of a digital unsharp mask.
I have a couple of thoughts, having shot medium format for a number of years and also using a Leica:
1. There is one less stop of DoF when you move from 35mm to MF. I.e., f4 on MF will look like f2.8 when shot on 35mm.
2. The mirror on the Pentax is a big heavy thing. You can easily hear it go "WHOP!" when you take a shot. I generally use mirror lock up when shooting at speeds slower than 1/100s.
3. MF has more detail, and will quickly show your deficiencies in less than perfect focus, unsteady tripod, etc.
Kent in SD
Well, the reason, based on decreasing probability is:
1.) The graininess of the smaller negative gives you the impression of more sharpness.
2.) The bigger format forces you to use either slower shutter speeds (for the same DoF), or wider apertures.
Add to that the huge mirror slap (compared to Leicas), so it's easier to miss focus or have motion blur.
Another possibility could be flare and contrast.
Maybe the particular lens you used in MF flares easily and is lower contrast than the 135 lens you usually use.
Contrast can make a big difference in sharpness perception.
That said, almost all system MF cameras after '60s can easily outperform even the sharpest 35mm systems, due to the big difference in frame size.