Steve Spencer
Offline
• • • • • • •
Upload & Sell: On
|
 p.6 #12 · What Fuji GF lenses would you like to see? | |
gdanmitchell wrote:
I think you are misconstruing what I’ve said in general about the difference in DOF between miniMF and FF systems. If you look at my posts on the subject at my website (I can provide links again if you wish) you’ll see that I have long recognized that there are three possible ways of looking at the effects of the different aspect ratios, depending on your perspective.
In fact, I do usually prefer the 4:3 aspect ratio for my landscape photography (though I also use 1:1 and 16:9). That is the most favorable most favorable comparison between the two systems, and in round numbers it does provide an approximate 1-stop difference in DOF. That is why I am pretty consistent about using the shorthand description of the difference being “about 1 stop.” In fact, in a recent discussion here I was called out for that by another poster who pointed out that this is not quite accurate and that the difference can be smaller. (Apparently one cannot win photography forum discussions, but I digress.)
Regarding that less favorable comparisons…
If we use the traditional method of attempting (never perfectly) to rationalize the comparison of systems with different aspect ratios (using the frame diagonal distance) then the comparison comes up with a less than 1 stop difference. (Since most photographers — I’m an exception — tend to default to the base aspect ratio of the system they use, this is a legitimate comparison, an some would argue the most appropriate for general comparisons.)
The least benediction comparison for miniMF is if we imagine a photographer who prefers the FF 3:2 aspect ratio and would crop miniMF to get it. I’d have to go back to my website and look it up, but here the difference is a bit smaller. (And if you ever shoot those wide aspect ratios, like 16:9 or other panoramic formats, on miniMF the is ends up being the most accurate comparison.)
Apologies to those whose eyes glaze over at all of this minutiae, but I want us to be accurate.
Finally, I strongly disagree that looking to the extremely successful and popular FF camera world for concepts that could apply effectively to miniMF is a mistake. I don’t claim that miniMF lenses must match those of FF (however that might be measured) but the underlying concepts of FF systems are effective, quite useful, and familiar to photographers. And the biggest potential market for miniMF systems (unless you believe that this market should be limited to “reformed” film MF and LF photographers) is among FF photographers who are interested in “moving up” to the somewhat larger format… but who can’t or don’t want to give up the coverage and functionality of FF systems that makes them so effective.
BTW, Lee’s comments about the selection of Fujifilm zoom lenses is in line with my long-standing critique, namely that, regardless of he quality of individual lenses, they betray a lack of planning for a coherent system of GFX zoom lenses. Yes, you can now get close (see his three lens list) but you still have unnecessary gaps and no coverage beyond 200mm. I know Fujifilm can do better than this.
...Show more →
Dan you make all of this a lot more complicated that it has to be.
From biggest to smallest you have 645 film (56 X 42), 44 X 33, FF 35mm (36 X 24), APS-C (23.6 X 15.6), and m4/3rds (17.3 X 13).
If you use a 4 X 3 or any squarer aspect ratios like 5 X 4, or 1 X 1 the crop factors between each format are
645 film to 44 X 33 - 1.3X
44 X 33 to FF 35mm - 1.4X
FF 35mm to APS-C - 1.5X
APS-C to m4/3rds - 1.2X
If you use 3 X 2 aspect ratio or any skinnier aspect ratio like 16 X 9 or panorama the crop factors for each format are
645 film to 44 X 33 - 1.3X
44 X 33 to FF 35mm - 1.2X
FF 35mm to APS-C - 1.5X
APS-C to m4/3rds - 1.4X
Obviously aspect ratio matters and not surprisingly when comparing 4 X 3 and 3 X 2 aspect ratio shaped sensors the 4 X 3 shaped sensors do better relative to the 3 X 2 shaped sensors when 4 X 3 aspect ratios are preferred and conversely 3 X 2 sensors do better relative to 4 X 3 shaped sensors when a 3 X 2 aspect ratio is preferred.
The only common aspect ratio that falls in between is 7 X 5, and the crop factors for that format are
645 film to 44 X 33 - 1.3X
44 X 33 to FF 35mm - 1.3X
FF 35mm to APS-C - 1.5X
APS-C to m4/3rds - 1.3X
Those are exactly the same if you determine the crop factor by comparing at the diagonal.
In my mind each of these steps can be meaningful. A crop of 1.4X is a difference of a stop in depth of field. The only crop factor that is smaller than that across all aspect ratios is 645 film to 44 X 33. That crop factor is always 1.3 and of course doesn't vary between aspect ratios because both are native 4 X 3 aspect ratios. The crop factor that is always just a bit bigger than 1.4X is FF 35mm to APS-C. It too doesn't change based on aspect ratio because both types of sensors are a native 3 X 2 aspect ratio. That leaves us with 44 X 33 to FF 35 and APS-C to m4/3rds, whether that is bigger than 645 film to 44 X 33 or almost as big as FF 35mm to APS-C depends on the aspect ratio. For squarer aspect ratios like 4 X 3, 5 X 4, and 1 X 1 the crop factor is bigger than 645 to 44 X 33 and almost as big as FF 35mm to APS-C. For skinnier aspect ratios like 3 X 2, 16 X9 and panorama it is smaller than 645 to 44 X 33. You can reverse those characterization for APS-C to m4/3rds.
So is the difference between 44 X 33 and FF 35mm meaningful? It depends on what matters to you, but one thing you should think about is the aspect ratios you tend to use. If you use 4 X 3 or other squarer aspect ratios a lot it will definitely matter more than if you use 3 X 2 and other skinnier aspect ratios a lot. In between will of course be in between, but that will primarily be a 7 X 5 aspect ratio at least of the classic aspect ratios.
This really isn't complicated. Each step to a larger format is somewhat different from the one below it but not hugely so. The odd step is APS-C to FF 35mm that is just a bit bigger, but it really isn't that much bigger. FF 35mm to 44 X 33 is almost as big if you use a 4 X 3 or squarer aspect ratio a lot and m4/3rds to APS-C is almost as big if you use a 3 X 2 or other skinny aspect ratio a lot.
In practice you can simplify things a lot by thinking about each step to a bigger sensor should get you some differences in what they provide but it won't be huge and sometimes will depend on the aspect ratio you use (that is when the aspect ratios of the sensors differ). Any two steps, however, will be a big and quite noticeable change regardless of the aspect ratio.
I think Fuji has nicely understood this by making 44 X 33 sensors and APS-C sensors. They are quite noticeably different. Panasonic I think understands it as well making FF 35mm sensors and m4/3rds sensors. Sony, Canon, and Nikon mostly play in the FF game and just dabble in APS-C, IMO. Whereas Olympus has made the choice to go all in with m4/3rds. I like Fuji's choice as my favorite, but of course YMMV, and even I am happy to have a FF 35mm sensor camera as a nice balance between the two types Fuji makes.
What does this mean for GFX lenses? I think it means we will just have to agree to disagree about whether it is important to compare to FF 35mm sensors. I don't think the comparison to FF 35mm is nearly as crucial as you do. 44 X 33 cameras will always have advantages, but smaller lenses with longer ranges will always be an advantage of FF 35mm systems over 44 X 33 systems, just like smaller lenses with longer ranges are always an advantage of smaller sensors. What I think Fuji needs to do is build good lenses that make sense for 44 X 33 sensor cameras. These will have a shorter focal length range and be heavier than directly equivalent FF 35mm lenses. At the same time they can be built with slower apertures that has it own very distinctive advantage. And with the right set of four lenses you can still have a very wide coverage of focal lengths with 44 X 33 systems.
|
