Steve Spencer
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 p.31 #4 · Pre-order: Zeiss Batis 40mm f/2 CF ($1,299) | |
Simon Barker wrote:
You haven't moved on from the points you raised several pages ago, my point is if you want to contribute more on how the lens works you probably need to actually use it.
I know that is your point, but my point has been and continues to be that these threads in FM has never demanded that you buy the lens to comment. People have always been welcome to comment on the pictures that have been posted. You consistently don't pay attention to my comments and the photos and dismiss them. This is both ignoring data that could be relevant to understanding the lens and violates the spirit that typically is present on these preorder threads.
Simon Barker wrote:
And the relevance of that is?
The performance of this lens and your interpretation of it is obviously very important to you and that importance seems to allow you to dismiss any contribution I make. Also the fact that you have posted so little on FM may also mean that you simply don't understand the norms here that people who haven't bought the lens yet can and often make very useful contributions. Your suggesting that I can't make a contribution without buying the lens is just totally not in keeping with the history of these threads on FM.
Simon Barker wrote:
No, that's just you trying to argue your point without thinking how it actually works, under normal conditions your focus point should be roughly in the middle of the plane of focus but with this lens using either of those modes you'll find most of the plane of focus too far forward from the focus target, so even if it's managed to get the target in focus it'll look wrong because we're accustomed to how it should look with proper focus.
Just think about how nonsensical your argument is for a moment, if you had a front focusing lens on a DSLR would you a. reduce the aperture till the problem goes away and say hey there's no problem! or b. use micro adjust to get proper focus?...Show more →
Well this answer explains a lot. You seem to be assuming that with a DSLR that if a lens front focussed you can always solve it by micro adjust. That was not my experience with DSLRs. With several lenses micro adjust would work for some focus distances and not others. This was always one of my frustrations with DSLRs--microadjust would fix some focussing issues but make others worse. You don't seem to appreciate it is both perfect possible and not that uncommon for a lens to show different amounts of focus errors at different distances. So your assumption that a lens can be fixed with micro adjust and it will always work at all distances is just wrong.
And the situation you describe in which the focus is too far forward, then that is not a case in which the focus error is covered by the depth of field. If you can see the focus error and the image looks weird then that is not an error that is covered by DOF. If it is an error is covered by DOF then it ceases to be an error. If you can still see the front focus and it looks bad then it isn't covered by DOF. Please show me anywhere in this thread where someone posted a longer shot in which front focus is evident even if it just looks bad.
Simon Barker wrote:
I was referring to the test shots I did where every single photo was front focused, over several subjects, over several days in different conditions. Now that may mean I have especially bad copy but I doubt it because this seems too widespread and too consistent in behaviour and yes I do put more faith in my test shots than some family portraits in varying conditions but does it perfectly prove it? No of course not but that's why I keep telling you to get a copy of the lens so you can actually move the conversation beyond your initial assumptions.
Again you focus on the child's shirt photos and I again refer you to my squirrel analogy....Show more →
Once again I have not been making assumptions. I was reporting what I saw in photos and you are paying attention to my arguments if you think I was focusing on the child's shirt. That was just one source of the eyes in the photos that had consistent misfocus and not the one I commented on in the previous post and your squirrel analogy still makes no sense for the same reasons I posted in my last response. I won't post the same argument again.
Simon Barker wrote:
My point being is you're seeing one thing and assuming that must be the cause, I ask you why the same problem is occurring in photos where that thing you're seeing isn't there and you have no answer beyond to go back to that one thing and insist it's due to that.
The conversation I think has moved beyond that point so it makes little sense to keep bringing it up unless you can show something else that verifies it.
No, please pay attention. I have said nothing about causes. I have reported what I observe. I haven't made assumptions either. You keep making accusations of my making assumptions but you haven't even identified these assumptions and you won't be able to do so because I haven't made them. As I said I am not trying to provide answers to your questions. Instead I am reporting what I am seeing and adding more data by doing so. If you post your pictures, I would be happy to comment on them, but somehow I don't feel that my comments would be welcome.
Simon Barker wrote:
I never claimed you said that, I'm trying to explain to you that you keep telling people it's due to 'this' yet you're just going off the information we're providing you because we actually have the lens, I've heard your point, I disagree with it because it doesn't match up to other scenarios and you offer no explanation as for why. Again go back to my squirrel analogy, even if you're right in that one set that the squirrel caused a problem what about all the rest? I have asked you to suggest what I should test but you never bothered to take me up on that offer, which is odd if you're interested in finding the cause.
I don't think you're keeping an open mind at all, it just seems awfully important to you that your assumptions are correct but OK you've said your piece and I've said mine, I'll leave it at that as I can't see anything worthwhile coming out of us continuing raising the same points again and again....Show more →
Where you are wrong Simon is that I keep telling people it is due to "this," which is something that I never have said. Instead I reported what I observed. You don't seem to be able to tell the difference between an observation and a claim that something is a cause. You keep saying I have suggested a cause when I have not. Let me be clear. I don't know what the cause is. I think there are several possible causes more than one thing might even be wrong and I think we should keep an open mind and be open to other people's observations even if they don't have the lens. That has always been the way we have proceeded on these threads at FM. People who own the lens don't dismiss what others observe in the pictures that are posted. If you want me to suggest a test, then I will but such tests are demanding and require a lot of effort and time. I am always hesitant to suggest that to anyone but since you ask and you seem to be inferring something from my lack of response here would be my best suggestions for a decent test.
You need to have a real human subject. Because it is an AF issue some variables will not be easily controlled. This variability means you will need lots of shots. I would suggest two full sets of tests. One in good outdoor lighting and one in typical indoor lighting requiring ISO 3200 or so and a shutter speed of 1/200 at f/2. Make sure you keep the shutter speed up to 1/200 or so. Under each lighting scenario you would need to shoot about 100 shots and at least 5 different focus distances, for this lens .5m, 1m, 1.5m, 3m, and 10m ought to work pretty well. Ideally you would do this both for EyeAF with AF-C, and compare this to AF-C by selecting the AF point, under both lighting scenarios. That would be a good beginning of a test. I realize it is a ridiculous amount of testing, but I really think that sort of test is the place to begin.
Oh, and I have made it clear I think there are lots of possibilities to what is going on, so you can say you don't think I have an open mind, but I think I have shown I am open to the problem being the result of lots of different things. And you better be clear about what assumptions I am even making if you say I just want my assumptions to be right. I maintain I am not making any assumptions and frankly the repeated accusations that I am making assumptions when you can't even identify them is the weakest and silliest form of argument. It is a false charge with nothing backing it up.
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