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y
Joined: 11 Aug 2013
Posts: 308
Location: EU
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 Posted: Sun Aug 11, 2013 8:06 pm Post subject: Diagnose Mir-1V issue |
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y wrote:
Hi, I recently got an old Mir-1V 37/2.8. I was surprised by weird shot quality at f/4+. Is this just a common case of overexposure or something else? Thanks in advance.
These were shot with my EOS 400D at Av.
f/2.8
f/4
f/5.6
f/8
f/11
f/16
Last edited by y on Sun Aug 11, 2013 8:30 pm; edited 2 times in total |
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DigiChromeEd
Joined: 29 Dec 2009
Posts: 3460
Location: Northern Ireland
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| Posted: Sun Aug 11, 2013 8:25 pm Post subject: Re: Diagnose Mir-1V issue |
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DigiChromeEd wrote:
| y wrote: |
Hi, I recently got an old Mir-1V 37/2.8. I was surprised by weird shot quality at f/4+. Is this just a common case of overexposure or something else? Thanks in advance.
These were shot with my EOS 400D at Av.
f/2.8
f/4
f/5.6
f/8
f/11
f/16 |
Welcome to the forum y. You can't show photos or links in your first post - an anti-spam measure. From now on you'll be OK. 
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"I've got a Nikon camera, I like to take a photograph" - Paul Simon |
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themoleman342
Joined: 21 Oct 2007
Posts: 2190
Location: East Coast (CT), U.S.A.
Expire: 2013-01-24
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| Posted: Sun Aug 11, 2013 11:11 pm Post subject: |
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themoleman342 wrote:
Are you sure you were actually shooting at those apertures? The Mir has a "backwards" aperture ring system that commonly confuses people when they're not familiar it. |
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y
Joined: 11 Aug 2013
Posts: 308
Location: EU
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| Posted: Sun Aug 11, 2013 11:27 pm Post subject: |
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y wrote:
| themoleman342 wrote: |
| The Mir has a "backwards" aperture ring system that commonly confuses people when they're not familiar it. |
What do u mean by "backwards"?
It has the preset aperture - 2 rings. AFAIK you preset the maximum aperture by the classic aperture ring and then apply the iris closing itself by the 2nd ring.
So I set eg. f/8 on aperture ring and turned the other ring to terminal position. I can even see the iris closing; it should be ok, I guess. |
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iangreenhalgh1
Joined: 18 Mar 2011
Posts: 15679
Expire: 2014-01-07
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| Posted: Sun Aug 11, 2013 11:46 pm Post subject: |
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iangreenhalgh1 wrote:
For me, the peak of sharpness appears to be at f5.6. The f8 and smaller are less sharp. This could be diffraction, but I wouldn't expect that to kick in until somewhere between f8 and f11. I do see quite a lot of JPEG artifacts which makes it hard to judge and it seems like the EOS has overexposed the f8 and smaller shots.
I don't think there's anything wrong with the lens.
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I don't care who designed it, who made it or what country it comes from - I just enjoy using it! |
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Aanything
Joined: 27 Aug 2011
Posts: 2187
Location: Piacenza, Italy
Expire: 2014-05-30
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| Posted: Mon Aug 12, 2013 4:38 am Post subject: |
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Aanything wrote:
Are you setting the corresponding aperture value on the camera body?
With my cameras, when using manual lenses with Chipped adapters (that allow you to set the aperture value on the body) I always must be sure that the body is set to the widest aperture value available.
This because the camera with auto lenses actually meters wide open and closes the iris only when you actuate the shutter.
This Will cause over exposition that grows as you set narrower apertures on the body, that looks like your case.
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y
Joined: 11 Aug 2013
Posts: 308
Location: EU
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| Posted: Mon Aug 12, 2013 6:09 am Post subject: |
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y wrote:
| Aanything wrote: |
| Are you setting the corresponding aperture value on the camera body? |
Sadly my adapter doesn't react on body's settings - it just shows f/2.
Thanks for your answers |
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buerokratiehasser
Joined: 12 Jun 2011
Posts: 470
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| Posted: Mon Aug 12, 2013 6:30 am Post subject: |
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buerokratiehasser wrote:
I dont know what you mean but f8 looks overexposed. However you managed to do so - it may have been the aperture not really f8, or user error on camera |
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themoleman342
Joined: 21 Oct 2007
Posts: 2190
Location: East Coast (CT), U.S.A.
Expire: 2013-01-24
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| Posted: Mon Aug 12, 2013 3:20 pm Post subject: |
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themoleman342 wrote:
| Quote: |
What do u mean by "backwards"? Smile
It has the preset aperture - 2 rings. AFAIK you preset the maximum aperture by the classic aperture ring and then apply the iris closing itself by the 2nd ring.
So I set eg. f/8 on aperture ring and turned the other ring to terminal position. I can even see the iris closing; it should be ok, I guess. |
Yup, that sounds like the correct procedure. Sometimes people will have the top ring set to f16 so the second ring moves in the full range, then they pay attention to the dot on that ring thinking it corresponds to the numbers on the top (which it doesn't): When the dot is at f2.8 the aperture is stopped down and when the dot is at f16, it's wide-open, so it moves backwards in a sense. |
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y
Joined: 11 Aug 2013
Posts: 308
Location: EU
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| Posted: Mon Aug 12, 2013 4:00 pm Post subject: |
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y wrote:
| themoleman342 wrote: |
| Sometimes people will have the top ring set to f16 so the second ring moves in the full range, then they pay attention to the dot on that ring thinking it corresponds to the numbers on the top (which it doesn't): When the dot is at f2.8 the aperture is stopped down and when the dot is at f16, it's wide-open, so it moves backwards in a sense. |
Now I get it. |
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bobcominitaly
Joined: 22 May 2009
Posts: 71
Location: Terontola (I)
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| Posted: Tue Aug 13, 2013 8:41 am Post subject: |
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bobcominitaly wrote:
It looks like the progressive overexposure I also used to have with manual lenses on my 40d. The more you close the aperture, the more the camera's TTL metering is off. To be sure, redo the series using the camera's M position and calculating the correct shutter time on the basis of a correctly (widen open) exposed shot. Of course, you can also just check it in the A position: if your shutter values start to differ progressively from what they should be when you close the aperture you know your TTL metering is the culprit.
FYI: a correct A / T series should look like this:
A.........................T
2.8................... baseT (e.g. 1000)
4.......................2x bT (500)
5.6....................4x bT (250)
8.......................8x bT (125)
etc. (of course, actual shutter times are increasingly smaller since expressed in fractions of a second, but it's easier to write it down this way) |
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y
Joined: 11 Aug 2013
Posts: 308
Location: EU
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| Posted: Tue Aug 13, 2013 9:24 am Post subject: |
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y wrote:
| bobcominitaly wrote: |
| redo the series using the camera's M position and calculating the correct shutter time on the basis of a correctly (widen open) exposed shot. |
Yea, I thought I would do that. I'll let you know. |
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y
Joined: 11 Aug 2013
Posts: 308
Location: EU
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| Posted: Wed Aug 14, 2013 2:13 pm Post subject: |
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y wrote:
I did my homework. These are results from my body's TTL at Av position:
A.........................T
2.8................... 640
4.......................320
5.6....................160
8.......................80
11.....................50/40
16.....................20
It seems the TTL metering is fine. |
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