AF Module analysis..

PistnbrokePistnbroke Posts: 1,221Member
edited March 2015 in Nikon DSLR cameras
Previouly commented on poor AF performance particularly in AF-S mode on the D7100 . An analysis of the modules gives the reason .
D7100/7200 at f8 1 cross sensor in use
D610/D7000 at f8/5.6 7 cross sensors in use
D750/D8xx at f8 11 cross sensors in use

So we see why in my case an upgrade from a D7000 to a D7100 was such a disaster and that a move to a D7200 would make no improvement.
With the bottom two cameras in lower light and low contrast the assisting sensors can find sufficient detail to make a focus but the poor old 7100 cannot .
Where to go from here ?? D610 but then I must buy two and two 28-300mm. This is not good for cashflow. Clearly the marketing value of 51 points outweighs the functionality of the 39 system.
I feel very disapointed ..I pay for an upgrade and get a downgrade but I dont feel a Canon comming on .
Post edited by Pistnbroke on

Comments

  • funtagraphfuntagraph Posts: 265Member
    edited March 2015
    Could you just give us a reference, where you got the information, D7000 can AF f/8 lenses? In my manual AF is limited to f/5.6.

    Besides, D7100 / D7200 have a wider range at the low light end (-3...+19) than D7000 (-1...+19), so I really don't think D7000 is more reliable for lenses at f/8 than the newer ones.
    Post edited by funtagraph on
  • PistnbrokePistnbroke Posts: 1,221Member
    From nikon site but as the cameras go out of production the spec gets truncated so your 5,6 is right.
    BUT the point is that on the 71/72 there is no support for the single centre sensor . I am sure 95% of D7100 users are happy with there use but I find every week the 7100 will not come to focus in normal room lighting with low contrast subjects while the D7000 always did . This is a very very big problem for me .
    I look for a reason and a solution ...
  • heartyfisherheartyfisher Posts: 3,108Member
    edited March 2015
    Maybe its just the Multi-CAM 4800 focus module that has the better capability to focus on low contrast subject. Sometimes engineers will compromise certain parameters when designing new products. It reminds me of when I "upgraded" to the D7000 from the D200.. which has 11 focus points but seem to acquire focus better in some situations..
    Post edited by heartyfisher on
    Moments of Light - D610 D7K S5pro 70-200f4 18-200 150f2.8 12-24 18-70 35-70f2.8 : C&C very welcome!
    Being a photographer is a lot like being a Christian: Some people look at you funny but do not see the amazing beauty all around them - heartyfisher.

  • sevencrossingsevencrossing Posts: 2,800Member
    edited March 2015
    . Sometimes engineers will compromise certain parameters when designing new products..
    +1
    The term "upgrade" like "Professional" is pretty meaningless
    Don't assume the latest model will be better for you in all respects
    Not every one felt the D800 was an upgrade to the D700
    a friend still prefers his D3s to his D4 for a lot of jobs

    Post edited by sevencrossing on
  • manhattanboymanhattanboy Posts: 928Member
    I still prefer leaded gasoline/petrol, but it is difficult to find.
    jk of course.
    There is something seriously off if people think that the D7000 is focusing better in low light compared to the D7100. Low light capability was added with the 7100 not removed, and for the most part I have found that the 7100 does great. For the first time on a DX sensor I could shoot pics at night with AF. What lens are folks using? Use something 2.8 or wider for these indoor/night shots. The f8 capability was really only for desperate birders who have renal failure and cannot afford to sell their kidney to get a proper supertele.
    The only caveat I can think of is that my D7100 was serviced by Nikon so maybe that would be my only recommendation if you are at the limits of your frustration.
  • PistnbrokePistnbroke Posts: 1,221Member
    No body makes a f2.8 or even F4 that goes from 18mm to about 150mm and there is the problem .

    "for the most part the 7100 does great" the most part is not good enough particularly when the failure time is when the bride kisses the groom
  • manhattanboymanhattanboy Posts: 928Member
    No body makes a f2.8 or even F4 that goes from 18mm to about 150mm and there is the problem .

    "for the most part the 7100 does great" the most part is not good enough particularly when the failure time is when the bride kisses the groom
    I see your point. The only possible solutions I can think of for that situation may not be helpful to you unfortunately, but may spark ideas to help tackle the problem.
    For example, one could shoot dual body with one being a wide aperture prime for those moments that are critical. 18mm is really tough on DX, but the nice folks here at the forum might have suggestions; the only thing that comes to mind fitting the bill is the Sigma 18-35mm f/1.8 DC HSM Art. The 2.8 zooms might be good enough for 24mm all the way out to 200mm; it would be nice to see a focus comparison test done with a 2.8 zoom versus 1.4 or 1.8 prime in the dark. If anyone knows of one, I would be interested to see it (thanks in advance). The other alternative is to use something like the 910 in non-flash mode to temporarily throw a high contrast target to allow focus. You could get the same effect shooting without the flash albeit more slowly using live view.
  • spraynprayspraynpray Posts: 5,351Moderator
    No body makes a f2.8 or even F4 that goes from 18mm to about 150mm and there is the problem .

    "for the most part the 7100 does great" the most part is not good enough particularly when the failure time is when the bride kisses the groom
    I see your point. The only possible solutions I can think of for that situation may not be helpful to you unfortunately, but may spark ideas to help tackle the problem.
    For example, one could shoot dual body with one being a wide aperture prime for those moments that are critical. 18mm is really tough on DX, but the nice folks here at the forum might have suggestions; the only thing that comes to mind fitting the bill is the Sigma 18-35mm f/1.8 DC HSM Art. The 2.8 zooms might be good enough for 24mm all the way out to 200mm; it would be nice to see a focus comparison test done with a 2.8 zoom versus 1.4 or 1.8 prime in the dark. If anyone knows of one, I would be interested to see it (thanks in advance). The other alternative is to use something like the 910 in non-flash mode to temporarily throw a high contrast target to allow focus. You could get the same effect shooting without the flash albeit more slowly using live view.
    If you think you've already got focus issues, DON'T get an 18-35 f1.8! Seriously, they can make a monkey out of a good body.

    There are obviously differences in style and technique between us @Pistnbroke because when I tested the D7000 against the D7100 for hi-ISO noise and low light AF using a 50/1.4, I found the D7100 clearly better, but me saying that doesn't mean you aren't right about your gear, settings and venues. All I would suggest is forget the specs, actually try a D610/750 and be sure that it does what you want before you swap out your body for it. Some specs have a habit of being better than reality IME.
    Always learning.
  • IronheartIronheart Posts: 3,017Moderator
    @Pistnbroke, do you have more than one D7100 and are they all acting the same way in low light? I just wonder if you have a bum one. Have you been able to get your hands on a D7200 to see if that may do the trick? I know we flogged this a bit to death on the thread about the AF assist options...
  • funtagraphfuntagraph Posts: 265Member
    If you think you've already got focus issues, DON'T get an 18-35 f1.8! Seriously, they can make a monkey out of a good body.
    A wrong conclusion stays a wrong conclusion even when somebody repeats it 2000 times. ;)

    I understood you have no own experiences with that lens? and the only person you KNOW (and not heard or read about…) is your buddy with his outdated Canon 7D? Yes there were reports about focus problems with certain bodies. Old ones, mostly. A 70D behaved much better, like DPReview found.

    Some people can handle the lens and are able to learn how to focus with it, others may need longer or never get it. I don't think it's worth to make it a personal crusade, especially because you have only limited experience on it.

    The topic was about D7000 better AF than D7100 / D7200? How about staying on topic? Instead of raving around? Anyway, limiting the AF by slow lenses might be a bad idea. But I also didn't find a D7100 AF to work wonders, sometimes it did miss - but that was my experience with fast primes on it as well. In some ways I never got attached to it like I did with D7000, I just thought we had a bad start - RAW converter was not ready, shutter pretty loud and in a way sounding cheap (don't beat me, it's only personal taste). I'd prefer the D750 to any of those "new" D7xxx. Pity I can't try my sold 18-35/1.8 with it. I liked it's colors and this incredible sharpness wide open.
  • heartyfisherheartyfisher Posts: 3,108Member
    edited March 2015
    Maybe you can consider the D5500 .. Has the better sensor, expeed4 and the 4800 focus module ..
    When I had a play with it in the store and compared it with the D7100, also in the store, it seemed to focus faster..

    However, I would think the D7100 would focus better in low light.. (from the spec sheet)
    Post edited by heartyfisher on
    Moments of Light - D610 D7K S5pro 70-200f4 18-200 150f2.8 12-24 18-70 35-70f2.8 : C&C very welcome!
    Being a photographer is a lot like being a Christian: Some people look at you funny but do not see the amazing beauty all around them - heartyfisher.

  • manhattanboymanhattanboy Posts: 928Member
    edited March 2015
    Does anyone know how much the AF speed varies with lens aperture?
    Based off of TC use I am hearing roughly 50% rediction for each stop.
    Also does anyone know if Nikon is similar to Canon with high resolution AF points?
    Post edited by manhattanboy on
  • PB_PMPB_PM Posts: 3,552Member
    Nikon does not have double cross points like Canon, or enhanced AF for F2.8 or faster lenses, at least not that they advertise. AF is the same from Fx.x-F8. Obviously there is decreased performance as light drops off.
    If I take a good photo it's not my camera's fault.
  • spraynprayspraynpray Posts: 5,351Moderator
    If you think you've already got focus issues, DON'T get an 18-35 f1.8! Seriously, they can make a monkey out of a good body.
    A wrong conclusion stays a wrong conclusion even when somebody repeats it 2000 times. ;)

    I understood you have no own experiences with that lens? and the only person you KNOW (and not heard or read about…) is your buddy with his outdated Canon 7D? Yes there were reports about focus problems with certain bodies. Old ones, mostly. A 70D behaved much better, like DPReview found.

    Some people can handle the lens and are able to learn how to focus with it, others may need longer or never get it. I don't think it's worth to make it a personal crusade, especially because you have only limited experience on it.

    The topic was about D7000 better AF than D7100 / D7200? How about staying on topic? Instead of raving around? Anyway, limiting the AF by slow lenses might be a bad idea. But I also didn't find a D7100 AF to work wonders, sometimes it did miss - but that was my experience with fast primes on it as well. In some ways I never got attached to it like I did with D7000, I just thought we had a bad start - RAW converter was not ready, shutter pretty loud and in a way sounding cheap (don't beat me, it's only personal taste). I'd prefer the D750 to any of those "new" D7xxx. Pity I can't try my sold 18-35/1.8 with it. I liked it's colors and this incredible sharpness wide open.
    Actually funnygraph, his second body is a 70D and it misses focus with that too. Speak to the dealers, they do see a lot of people complaining about low light focusing. Pointless having a lens that does f1.8 if it misses focus. Sure, it's sharp as all hell when it actually focusses on the subject which is no good for weddings.

    As to your comment about out dated 7D? Rubbish. I wish my crop sensor Nikons focused as well as the 7D.
    Always learning.
  • PistnbrokePistnbroke Posts: 1,221Member
    edited March 2015
    Well ha ha getting back on topic ..I have two D7100 and Two 18-140 and both I and the wife have the same problem ..now been thinking ..when I changed to the 7100 I was using the Sigma 18-200 and do not remember focus issues (only LCD issues) but I maybe only did one wedding with that combo So best find if its the lens ..both came from same supplier grey market . A friend of mine who uses the same combo at weddings has no problem.
    Think I will try another lens next time out maybe the 28-300 Nikon but I cannot mess about as the rings are being delivered to the best man by an owl....BIF at a wedding holy .....
    Post edited by Pistnbroke on
  • funtagraphfuntagraph Posts: 265Member
    Ring delivery by an owl? Harry Potter wedding? ;))

    Sorry @Spraynpray, I sold my 18-35/1.8 to somebody with a D7100 and had no complaints. And of course I didn't know about 70D but when rechecking the article, it's advance was in single AF (not continuos) - so, to me that wouldn't be a big advantage since I use AF-C nearly exclusively. All I can say, I didn't notice a lot missed focus pics but when it was off, it was always in wide angle and I thought it was because of the huge AF frames.

    @pistnbroke, I would not recommend 28-300. It was not a great performer wide and pretty lousy at 300. Heavy and sucked in a lot of dust tot he sensor.

    Due to the featured P900 in the main blog I thought about getting such a cheap supertele. Okay, it's only JPG, but for candid shots I expect no worse quality than a 28-300 on any DX.
  • PB_PMPB_PM Posts: 3,552Member
    edited March 2015
    ...18-140...the Sigma 18-200...
    There are your problems right there, slow, variable aperture lenses. Let me guess, AF is always worse at the long end of the zoom range. :)
    Post edited by PB_PM on
    If I take a good photo it's not my camera's fault.
  • heartyfisherheartyfisher Posts: 3,108Member
    edited March 2015
    I have had a play with a friend's 28-300 .. Its ok on Fx but its not as sharp as the 18-140. I would consider either of the 18-300 before the 28-300, on a DX camera like the D7100.
    Post edited by heartyfisher on
    Moments of Light - D610 D7K S5pro 70-200f4 18-200 150f2.8 12-24 18-70 35-70f2.8 : C&C very welcome!
    Being a photographer is a lot like being a Christian: Some people look at you funny but do not see the amazing beauty all around them - heartyfisher.

  • PistnbrokePistnbroke Posts: 1,221Member
    edited March 2015
    All good and helpfull comments . I already have the 28-300 for my D800..Thought I might stick it on the D7100 for the next lot of speeches...but I ask myself why a 5.6 140 gives a problem and a sigma 18-270 did not?? and why an 18-270 gave no problem on the D7000.
    I dont regard people sitting eating a wedding breakfast or making speeches a low light situation..maybe a lot of white and maybe backlit . Plenty of contrasty edges to pick ..Then ask why my friend with the same kit has no problems at his weddings???
    The 18-200 would be a good solution if it worked but then why would it and not the 18-140.
    All very confusing and subject to testing ..very difficult to simulate at the studio..You could do 2 or 3 weddings and have no problem then the next its a total pig. Will make better attempt to analyse the situation.
    Considering the 24-120 f4 on the D7100 which in combination with the 17-35 on the D800 covers the situation but it starts to get expensive when you want two !!!
    Post edited by Pistnbroke on
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