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02-20-2010, 10:09 PM   #241
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New question for A*400mm f/2.8 lens owners. Regardless how I use the lens, with or without a TC, after 1,000 shots I have yet to get a STEADY focus point select square and focus indicator. It continues to blink on and off and beep. No amount of fine tuning on a static object can aquire a stop the blinking and beeping. I do not have this problem with my DA*300 + 1.4x TC at 420mm. But I can not get the 400mm lens itself to a focus point where it sticks.

Any other A*400mm lens owners have this or is indicative of a problem.

Its not from lack of trying or variety of test cases.

Right now the 400 is just packed away as i'm disgusted with it.

02-21-2010, 12:43 AM   #242
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Lee,

I've read everything posted about your problems carefully.

You said:
"the focus wanders between shots."

Questions:
1. If you set everything up properly and sight in on a close, clear, stationary target does the lens appear to the eye to come to proper focus in the viewfinder when using manual focus?

2. "wanders between shots". By this do you mean that if you were to shot a series of shots using, say, continuous shooting mode and manual focus without touching the camera between shots that some images will be more in focus than others in the series or would they all be consistently out of focus to the same degree?

3. Have you ever gotten a good clear in focus image out of this lens no matter what the circumstances?

If you haven't done the above please do so and report back and we will take it from there.

I use the same head as you and use the Manfrotto 028 tripod. My tripod is rated at 26 pounds and has a cranked column which I use to lift up and down longer and heaver glass than yours with no problem.

Something is wrong.

Last edited by wildman; 02-21-2010 at 01:05 AM.
02-21-2010, 12:57 AM - 1 Like   #243
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Lee, I have no idea if this is correct, but my guess is that the DOF at 400mm f/2.8 may be so shallow that the focus detection system doesn't believe it's in focus even when it's really really close.

Edit with another question: Do you have a proper filter in the rear filter holder? I have heard that these rear filters are part of the optical design of this sort of lens, and sharpness suffers without one in place (however on my Tamron 400mm, I couldn't detect a difference with or without the filter).

Last edited by heliphoto; 02-21-2010 at 01:07 AM.
02-21-2010, 01:29 AM   #244
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I just picked up the 32 lb A* 1200....I have a tripod for medium format but this is too big. Any recommendations?

02-21-2010, 04:11 AM   #245
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QuoteOriginally posted by smc Quote
I just picked up the 32 lb A* 1200....I have a tripod for medium format but this is too big. Any recommendations?
A big wooden tripod from Wolf, Berlebach or a real video tripod from Vinten, Sachtler etc. will do the job. For the Vinten/Sachtlers etc. you should search the secondhand market, they can be very expensive new, especially if you look for a CF one. But the wooden ones are much cheaper and will do the job nicely, as wood (especially ash) will dampen and absorb any vibrations much better than any metall - and is much cheaper than a comparably big CF.

Ben
02-21-2010, 04:14 AM   #246
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QuoteOriginally posted by heliphoto Quote
Lee, I have no idea if this is correct, but my guess is that the DOF at 400mm f/2.8 may be so shallow that the focus detection system doesn't believe it's in focus even when it's really really close.

Edit with another question: Do you have a proper filter in the rear filter holder? I have heard that these rear filters are part of the optical design of this sort of lens, and sharpness suffers without one in place (however on my Tamron 400mm, I couldn't detect a difference with or without the filter).
I just looked at the lens diagram at Dimitrov's site and it shows the rear filter in place. So, you are probably correct, that it is part of the design. A rear filter would somewhat flatten the focal plain and also increase backfocal distance.

Nevertheless, I also think - as wildman qwrote - that a "flickering" of the focus confirmation is not unexpected, given the extremely shallow depth of field. On the other hand to get something into focus at near infinite distances is not too easy too, as it is very dependend on the weather (clraity of the air, local turbulences etc.). With my old 500/4.5 I can get rarely sharp shots of objects farther away than app. 100 meters, simply because of seeing influences.

Ben
02-21-2010, 04:51 AM   #247
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QuoteOriginally posted by smc Quote
I just picked up the 32 lb A* 1200.
No--you're not serious. Or are you? Somebody bought it!

02-21-2010, 06:51 AM   #248
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QuoteOriginally posted by imtheguy Quote
Any other A*400mm lens owners have this or is indicative of a problem.

Right now the 400 is just packed away as i'm disgusted with it.
I just set mine up on the tripod and did some testing. Yeah, I get a lot of blinking at my normal shooting apertures (f/6.3, f/7.1) but if I crank down to f/14 the indicator is steady as a rock. I can't comment on the beep: I haven't heard a camera beep yet (but then I can't hear my turn signal either ;~)
02-21-2010, 06:56 AM   #249
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QuoteOriginally posted by imtheguy Quote
Any other A*400mm lens owners have this or is indicative of a problem.
I just set mine up on the tripod and did some testing. Yeah, I get a lot of blinking at my normal shooting apertures (f/6.3, f/7.1) but if I crank it down to f/14, the indicator is on steadily. I can't comment on the beep: I haven't heard a camera beep yet but that's because I'm old and going deaf--I can't hear my turn signal either ;~)

QuoteOriginally posted by imtheguy Quote
Right now the 400 is just packed away as i'm disgusted with it.
Oh, no!
02-21-2010, 07:01 AM   #250
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QuoteOriginally posted by Ben_Edict Quote
I just looked at the lens diagram at Dimitrov's site and it shows the rear filter in place. So, you are probably correct, that it is part of the design. A rear filter would somewhat flatten the focal plain and also increase backfocal distance.

Nevertheless, I also think - as wildman qwrote - that a "flickering" of the focus confirmation is not unexpected, given the extremely shallow depth of field. On the other hand to get something into focus at near infinite distances is not too easy too, as it is very dependend on the weather (clraity of the air, local turbulences etc.). With my old 500/4.5 I can get rarely sharp shots of objects farther away than app. 100 meters, simply because of seeing influences.

Ben
QuoteOriginally posted by dadipentak Quote
I just set mine up on the tripod and did some testing. Yeah, I get a lot of blinking at my normal shooting apertures (f/6.3, f/7.1) but if I crank down to f/14 the indicator is steady as a rock. I can't comment on the beep: I haven't heard a camera beep yet (but then I can't hear my turn signal either ;~)
You guys are good! Now I will unpack and remount the A*400 f2.8 to try with a few different 49mm rear filters. I have already tried shots in excess of f/13 but will see if I can match DadiPentak's f/14 solid indicator.

Using a filter to make it MORE clear?? Interesting but willing to try anything.

Thanks!
02-21-2010, 07:13 AM   #251
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Just a few additional thoughts:

RE: Lee getting a heaver tripod, higher working load tripod and/or sand bags etc.

Instead of above get a tripod with leg stretchers. They can really firm up a heavily loaded tripod more efficiently than any of the above without any additional weight to speak of. Plus it makes it much easier to shift the rig about for short distances if you want to change your POV without taking the whole setup apart. Just pick it up and move it as a rigid unit.

Stretchers are rarely mentioned when talking about long lens tripods and I don't understand why.

It doesn't take rocket science to see that relatively narrow telescopic legs, extended out to 6 feet , with no bracing between them and connected to the head with only a narrow single pivot point and a working load of 20 pounds or more is a bad idea all else being equal. I don't care what kind of material the pod is made of.

Anyway a high working load rating does not necessarily say anything about rigidity, stiffness or vibration damping. It's just a gross working load rating.

Columns:
For me a column is essential. When following birds the line of sight often requires a slight tweak in height up or down to be comfortable.
For this you need a column and with the heavy loads of a long glass a manual column does not cut it. You just can't control that much weight well by trying to slide a heavy load up or down by hand. Use a well made geared crank with a smooth clutch action that allows you to adjust all the weight up and down a few inches precisely and quickly. Important also is the ability to raise and lower your rig while keeping your eye to the viewfinder - essential sometimes.

I have used the above setup up to 60x with good results - far more vibration prone than the typical 500mm telephoto at prime (15x).

Just a few of my many thoughts on a proper heavy long lens mount.
02-21-2010, 07:15 AM   #252
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QuoteOriginally posted by wildman Quote
Lee,

I've read everything posted about your problems carefully.

You said:
"the focus wanders between shots."

Questions:
1. If you set everything up properly and sight in on a close, clear, stationary target does the lens appear to the eye to come to proper focus in the viewfinder when using manual focus?

Yes

2. "wanders between shots". By this do you mean that if you were to shot a series of shots using, say, continuous shooting mode and manual focus without touching the camera between shots that some images will be more in focus than others in the series or would they all be consistently out of focus to the same degree?

Yes, focus wanders among a continuous set of shot made by remote or hand. Very evident at 50m and with rear converter, less evident w/o converter and when closer.

3. Have you ever gotten a good clear in focus image out of this lens no matter what the circumstances?

Never at distance and not sure of closer shots. Thats why I just sorted through the 1,000 I have taken in the last few days and put the lens away to see if ANY are really clear and if so what circumstances. I will post the best at close, medium and far to see what the gang thinks; is the best good enough.

If you haven't done the above please do so and report back and we will take it from there.



I use the same head as you and use the Manfrotto 028 tripod. My tripod is rated at 26 pounds and has a cranked column which I use to lift up and down longer and heaver glass than yours with no problem.

Something is wrong.
Thanks.

Postings on the way as soon as I figure best way. Will resize and put on my ISP server I guess.
02-21-2010, 07:50 AM   #253
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QuoteOriginally posted by Ben_Edict Quote
A big wooden tripod from Wolf, Berlebach or a real video tripod from Vinten, Sachtler etc. will do the job. For the Vinten/Sachtlers etc. you should search the secondhand market, they can be very expensive new, especially if you look for a CF one. But the wooden ones are much cheaper and will do the job nicely, as wood (especially ash) will dampen and absorb any vibrations much better than any metall - and is much cheaper than a comparably big CF.

Ben
Thanks Ben....I remember seeing a at a wood tripod at L&S but I'll need to see if it'll take the weight.....but you're right, I don't need something new...

QuoteOriginally posted by dadipentak Quote
No--you're not serious. Or are you? Somebody bought it!
Now I have to take some reasonable shots with it.......

Steve
02-21-2010, 08:17 AM   #254
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QuoteOriginally posted by smc Quote
Now I have to take some reasonable shots with it....... Steve
Taking that as a "Yes, I really did buy it." I can only say, "Dude, you are the man!" Congratulations!
02-21-2010, 08:54 AM   #255
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QuoteOriginally posted by dadipentak Quote
Taking that as a "Yes, I really did buy it." I can only say, "Dude, you are the man!" Congratulations!
Dave: Yes, he did buy the lens! Threw in a "WTH" low bid and it was accepted. Stuff of dreams!

Look at this thread and begin at Post #12 (They can Bite Me . . . ).
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