vbuhay
Veteran Member
Not that kind of Bat! LOL, funnier by the day.
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D750: not happy with lowlight focus..
- Thread starter bvd
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- nikon d750
Laslo Varadi
Veteran Member
you are shooting the 50mm 1.8 wide open and it is soft wide open. Mine is try shooting slightly stopped down like F2.8. Mine is very sharp at f2.8 in your post below you also mention the Canon 24-70 f2.8. Assuming it is like my Nikon 24-70 F2.8 the it is sharper wide open then the Nikon 50mm. Also check to make sure you focused on the eye. You can set your camera to show where the focus area was.
jtan163
Senior Member
The A7s can see in the dark, granted.
But I have not heard a whole lot about how well it focusses.
grazuncle
Veteran Member
Where is the bat going to end up?
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snooked123
Forum Enthusiast
a- In low-light are you using the cross-type points? On my D700, the non-cross type points are generally less accurate and hunt in low-light
b- Are you having more issues with the Sigma or the Nikon 24-70 AFS? The AF on sigma lenses is reverse engineered and generally not as good as Nikon lenses.
b- Are you having more issues with the Sigma or the Nikon 24-70 AFS? The AF on sigma lenses is reverse engineered and generally not as good as Nikon lenses.
Dimitris Mitrovgenis
Forum Enthusiast
I am definitely focusing on the eye. I have shot 130000 pictures since 2005 when I started with digital. I am not a newbie. I will use off camera flash for more serious shooting but right now it seems that the outer focus points in the D750 are not accurate with the G-Series Lenses.
I have shot 3000 picture in a week to test the D750. In the same lighting the 5D was way more accurate.
Is the Af system really from the D4s? It seems handicapped to me.
I have shot 3000 picture in a week to test the D750. In the same lighting the 5D was way more accurate.
Is the Af system really from the D4s? It seems handicapped to me.
Albert Silver
Veteran Member
Three strikes and they were out.Where is the bat going to end up?
Hard to tell with bats, it depends on what their echolocation system is telling them.Where is the bat going to end up?
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There is a very fine line between 'hobby' and 'mental illness.' :'!':
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'You could look it up.' -Casey Stengel after James Thurber
olyflyer
Forum Pro
...in that case you have a VERY serious problem with the camera, or most probably with the lens. I mean, if you need to correct focus with the maximum possible value that is really very serious, so I'd suggest you do something about it, not just learn to live with it. I'd start with the lens, send it in to Sigma and get it tuned by them. There must be something seriously wrong with it. I use the Nikon 50/1.4G on the D800 and no focus correction is necessary, but if I needed anything more than + or - a few values then I'd send it to Nikon. +20 is totally unacceptable.
Increase the light. In low light contrast is very low, and especially if you have a lemon lens, like the Sigma seems to be, then focus may be totally impossible, or extremely difficult. Regardless which camera you have, you will always need something to focus on, the camera must see some contrasty target.
Check that lens, and/or increase the light.
That's strange. The LCD preview almost always looks better than the real PC screen.
olyflyer
Forum Pro
Are you sure you are testing and judging the D750 right? I mean, image sharpness depends on NR settings as well, if your NR is too severe details will be lost and the image may look clean, but soft. Post an image with EXIF to demonstrate your problems, but I really don't see why you would have problems shooting under that light.
It isn't really THAT dark if you can get 1/160s at f/2.8 and ISO8000. I calculated to 0.5 EV based on your data, and that is very far from -3EV, which the AF module is good for. Of course, that specification is only valid on test targets, so if you don't have enough contrast you can always have problems, but generally speaking, unless your camera is broken, I think any modern camera can focus under that light, especially the last models and SPECIFICALLY the D750.
The formula I used is this one, which I think is correct:
EV = LOG((f^2*100)/(shutter*ISO)) x (10/3)
LOG is the common (base-10) logarithm function
f is the f-stop
shutter is the shutter speed in seconds
ISO is the ISO setting
In other words, I have no idea how can you have such problems. I am very open minded and will never exclude faulty camera as a possibility, but I honestly doubt that you received 2 different D750, and both having trouble focusing at that light. I would suspect lens issues, or simple user error, or some other configuration issues, work flow or need for familiarization with the camera.
Dimitris Mitrovgenis
Forum Enthusiast
This is the kind of shots that I have trouble getting.I am using outer AF point AF-C group area AF.Check the EXIF data.What you think is wrong?
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500px.com/dimitrismitrovgenis
StillLearning
Veteran Member
Looking at the picture it appears to be front focused. The finger knuckle on the left hand looks more in focus. If that is the older Sigma 50mm F1.4 then looks about right from samples I 've seen. If it is the Sigma 50 Art then send the lens back for another. Group focus would have been what I would have used in the same situation. I don't think it is a matter not tracking as is it nailing the focus with the lens. Do you have any with another lens preferably nikon?This is the kind of shots that I have trouble getting.I am using outer AF point AF-C group area AF.Check the EXIF data.What you think is wrong?
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500px.com/dimitrismitrovgenis
I haven't had to shoot any toddlers since the film days when I used flash and f8. Photozone was not impressed with Sigma's older 50mm. Quote from their review of it.
"The Sigma AF 50mm f/1.4 EX DG HSM struggles to deliver convincing performance on full format cameras. The center quality of the lens is certainly fine and even great from f/2 onwards. Unfortunately the border & corner performance is rather disappointing. It's downright soft at large apertures and never really better than good even at the very best setting (f/8)."
Haven't had an occasion to shooting any action in low light. This is as close but it is in light 3 stops better then yours. Dealing with a very animated violinist. Like to jerk is head around while playing. Caught him at a small moment when I didn't get motion blur. Only so much 1/200 can do.
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michaeladawson
Forum Pro
Are you sure about that calculation? Not saying you're wrong, but every EV chart I look at says that f/2.8 at 1/160s shutter speed is roughly EV 10.5 at ISO 100. Subtracting 1 EV for every doubling of ISO up to 8000 would indicate subtracting about 6.5 EV for a final EV value of about 4.0. Maybe the equation should be using LN instead of LOG?
Art Jacks
Veteran Member
Have you tried a slower shutter speed and F4 or F5.6 ?
Dimitris Mitrovgenis
Forum Enthusiast
This is the 50 mm 1.8G.I have only Nikon Lenses.The lenses are calibrated with Reikan focal all of them and they are spot on when I used them in stationery subjects.
Dimitris Mitrovgenis
Forum Enthusiast
Yes I have tried but whats the point to have fast primes if you are using them @ f4?
It just a bit better when I stop down.When the ISO goes high the focus accuracy is going way down.This is the same with both cameras that I got at the moment.
Art Jacks
Veteran Member
Sometimes with a non static subject you have to use an appropriate aperture to capture the subject sharpness you require, I have several F1.4 lens but that does not mean I use 1.4 all the time just because it is available, I select an aperture that will give me the sharpness I need, it is a decision only you can make, do you want a sharp image and a little less OOF or continue as you are ?, one of the online DoF calculators should give you an idea of how deep the DoF zone at f2.8 is.
Dyun27
Veteran Member
Here's the deal. Just because a lens gives one the option of shooting at f/1.4, it doesn't mean that f/1.4 is a good choice every time. The depth of field is so narrow, that any movement or misalignment is going to show right up, especially at slower shutter speeds when camera shake (due to not-so-steady hands holding that camera) can creep into the picture and add additional blur.The outer points get confused very very easily. Was it with the centre one?Same case I described in the previous photo. Focus is sharpest on the baby's sleeve. Maybe some fine-tuning is in order. At f/1.4 the DOF is just so tiny, it's going to be very difficult to nail focus every time even with a fine-tuned lens.an other one. This is the sharpness i get i think i have to be happy with. SOOC, RAW, no sharpness applied, little crop.
focused on the front eye near the nose.
With some sharpness applied it looks good to me...
attached full jpg.
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https://www.flickr.com/photos/jpivkova/
Can somebody post a sharp picture indoors preferably high ISO?
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500px.com/dimitrismitrovgenis
It might be OK if you're shooting a flat subject where the entire subject fits into that tiny DOF (a piece of paper with black print facing the lens straight-on for example), but a very curvy, 3-dimensional subject is going to have only a tiny portion of it within the DOF. In the above picture that happens to be the small section of cloth on the sleeve of the baby.
Distance from the subject is also going to influence this. The closer you get to the subject at f/1.4, the less of that subject is going to be in focus. The farther you stand from the subject, the more of it is going to be in focus even when shooting wide open at f/1.4.
Then there is the question of which f/1.4 lens was used. Most of them are just not sharp wide open. Yes, you have the option to shoot with them at f/1.4, but closed down to at least f/1.8 to f/2.8 is ideal for better sharpness and more DOF, especially if you're close to the subject.
I own a Nikkor 50mm f/1.4G. Great lens when stopped down just a bit, sharp, but at f/1.4 there is some softness. When using third-party lenses like Sigma's older primes, they can be even softer wide open, not to mention the fact that they could have compatibility issues with newer cameras as far as focus goes. This is why some more fortunate photographers choose to shell out a couple thousand dollars on a more expensive Nikon or Zeiss lens to get sharper results even wide open.
There are so many factors that come into play here, that simply from looking at a photo even with the EXIF info attached is not going to be enough to conclusively state that it's the camera's fault or the lens, or the user. All of these things have to be looked at before coming to a conclusion. It happens too often that people first blame the equipment instead of themselves. Showing examples of someone who successfully photographed a child at f/1.4 with this or that camera proves nothing, because we don't know how many shots had to be taken until the successful one was achieved. We don't know the skill of the photographer or how sharp the lens was, etc. Too many variables. Did I mention that crop sensor cameras will give f/1.4 slightly more DOF and use the sharpest portion of a lens, which is the center? Full frame has even less room for error.
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https://www.flickr.com/photos/jpivkova/
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StillLearning
Veteran Member
StillLearning
Veteran Member
I calculated your shot at EV 6.97The outer points get confused very very easily. Was it with the centre one?Same case I described in the previous photo. Focus is sharpest on the baby's sleeve. Maybe some fine-tuning is in order. At f/1.4 the DOF is just so tiny, it's going to be very difficult to nail focus every time even with a fine-tuned lens.an other one. This is the sharpness i get i think i have to be happy with
focused on the front eye near the nose.
With some sharpness applied it looks good to me...
attached full jpg.
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https://www.flickr.com/photos/jpivkova/
Can somebody post a sharp picture indoors preferably high ISO?
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500px.com/dimitrismitrovgenis
This one is EV 6.29
EV 5.97
Last edited:
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