[EssJayEff]

Can you record the serial number and condition here in the Pentax Serial Number Database for future reference?

[MossyRocks]

I have the A* 400/2.8 and I picked it up for $2700 in the middle of last year. It had some scuffs on the lens barrel but only minor and looks to be from normal use not abuse. So given yours has a crack in a lens element I would be running from it.

[c.a.m]

I would also recommend returning the lens for a full refund.

Another thought is that if you were to sell the lens in the future, you may find it difficult to recover your cost -- many potential buyers would shy away from a cracked element.

- Craig

[Just1MoreDave]

I would also recommend returning the lens for a full refund.

Another thought is that if you were to sell the lens in the future, you may find it difficult to recover your cost -- many potential buyers would shy away from a cracked element.

- Craig

That's what I think. Picture yourself writing the listing to sell it. "Except for the crack and the oily aperture and the filter..."

[Not a Number]

Get your money back. You'll never be happy with the lens no matter what you end up pay for it. And the crack will just get worse.

[MalcS]

Can you record the serial number and condition here in the Pentax Serial Number Database for future reference?

Added to database.

[angerdan]

The DA 560 is too much $$$ for me I think.

It's below $3000 used.

[DeadJohn]

Sticky aperture and cracked glass on a lens for which parts are tough to find would be a dealbreaker for me. Imagine if DIY cleaning doesn't fix the aperture, you send it to KEH, and they find it needs some part that is no longer available. The glass crack looks like it's all the way through, so shouldn't expand out into the middle of the glass, but glass chips could be floating around inside contributing to the aperture issue.

I would only take the risk keeping that lens if the seller was willing to drop the price from $2600 to the $500 range. That makes it a good gamble on your part. Note that after you try cleaning the aperture, the seller can reasonably refuse to take a return, because they can't tell whether you made things worse.

_____________________________

As an alternative, consider a 6" Schmidt-Cassegrain telescope for an inexpensive 1500mm focal length f/10 lens. It will be slow manual focus but at that distance it should be relatively easy to keep in focus. Your location is "Virginia" so I assume you'll be photographing Wallops launches; those are medium size rockets and 1500mm probably won't be too much focal length. f/10 seems slow for night launches but the bright glow of rocket exhaust will be a limiting factor regardless of aperture.

If you decide to go the telescope route, I suggest ordering from High Point Scientific because of their outstanding technical support. They can help match a t-ring for your camera, a t-to-SCT or t-to-eyepiece adapter for the telescope, and a tripod adapter for your existing tripod (if heavy duty) or a new tripod. Celestron C6-A SCT | Purchase Celestron C6-A SCT Aluminum Optical Tube, Celestron Optical Tubes Online at High Point Scientific

[Kerrowdown]

Pentax - A 400mm F2.8 insanity.... advice

I'm in the send it back camp... bide your time with your money in your pocket.

We have a phrase hereabouts... "If is meant, it wont pass you by"

[MalcS]

It's below $3000 used.

Haven’t seen one used recently, but will certainly keep an eye out!

[gatorguy]

As an alternative, consider a 6" Schmidt-Cassegrain telescope for an inexpensive 1500mm focal length f/10 lens. It will be slow manual focus but at that distance it should be relatively easy to keep in focus. Your location is "Virginia" so I assume you'll be photographing Wallops launches; those are medium size rockets and 1500mm probably won't be too much focal length. f/10 seems slow for night launches but the bright glow of rocket exhaust will be a limiting factor regardless of aperture.

If you decide to go the telescope route, I suggest ordering from High Point Scientific because of their outstanding technical support. They can help match a t-ring for your camera, a t-to-SCT or t-to-eyepiece adapter for the telescope, and a tripod adapter for your existing tripod (if heavy duty) or a new tripod. Celestron C6-A SCT | Purchase Celestron C6-A SCT Aluminum Optical Tube, Celestron Optical Tubes Online at High Point Scientific

Now THAT'S an interesting option. Hmmm, I have a use case where that might work out quite well. Have you done this yourself?

[MalcS]

Sticky aperture and cracked glass on a lens for which parts are tough to find would be a dealbreaker for me. Imagine if DIY cleaning doesn't fix the aperture, you send it to KEH, and they find it needs some part that is no longer available. The glass crack looks like it's all the way through, so shouldn't expand out into the middle of the glass, but glass chips could be floating around inside contributing to the aperture issue.

I would only take the risk keeping that lens if the seller was willing to drop the price from $2600 to the $500 range. That makes it a good gamble on your part. Note that after you try cleaning the aperture, the seller can reasonably refuse to take a return, because they can't tell whether you made things worse.

_____________________________

As an alternative, consider a 6" Schmidt-Cassegrain telescope for an inexpensive 1500mm focal length f/10 lens. It will be slow manual focus but at that distance it should be relatively easy to keep in focus. Your location is "Virginia" so I assume you'll be photographing Wallops launches; those are medium size rockets and 1500mm probably won't be too much focal length. f/10 seems slow for night launches but the bright glow of rocket exhaust will be a limiting factor regardless of aperture.

If you decide to go the telescope route, I suggest ordering from High Point Scientific because of their outstanding technical support. They can help match a t-ring for your camera, a t-to-SCT or t-to-eyepiece adapter for the telescope, and a tripod adapter for your existing tripod (if heavy duty) or a new tripod. Celestron C6-A SCT | Purchase Celestron C6-A SCT Aluminum Optical Tube, Celestron Optical Tubes Online at High Point Scientific

Agreed on all points! At this point I’m 99% on sending back and forgetting about it, lest it become another box in the basement...

SCT’s - that’s an idea. I have an 8” Celestron in a gps/computerized fork mount, so I know the ins and outs. I suppose a small (relatively) refractor might be a possibility too, though I’ve never used one for terrestrial, but APOs tend to be up there in price, and achromats are the definition of CA. I’ve bought from High Point before.

[bigdavephoto]

I'm slightly in the camp of sending it back. At the same time, I think testing it before sending it back would be the way to go. If the crack does not affect any picture, I think trying to get the seller to refund a large portion of the sale price could be a good thing.

[DeadJohn]

Now THAT'S an interesting option. Hmmm, I have a use case where that might work out quite well. Have you done this yourself?

I've used SCT (and other) telescopes mostly for astrophotography.

I haven't had many opportunities for terrestrial objects through a telescope. Haze and wind become major factors when photographing something distant, especially at sea level. One lighthouse I frequently photograph becomes a blurred mess beyond 500mm focal length because of air distortion.


SCT telescopes are compact, sharp, and inexpensive when you consider their extreme focal lengths. The tradeoffs are long minimum focus distance, precise but slow focuser, and ugly donut bokeh on out of focus highlights. Those tradeoffs don't matter when photographing objects miles away since you'll be focused at near-infinity the whole time.

[gatorguy]

I've used SCT (and other) telescopes mostly for astrophotography.

I haven't had many opportunities for terrestrial objects through a telescope. Haze and wind become major factors when photographing something distant, especially at sea level. One lighthouse I frequently photograph becomes a blurred mess beyond 500mm focal length because of air distortion.


SCT telescopes are compact, sharp, and inexpensive when you consider their extreme focal lengths. The tradeoffs are long minimum focus distance, precise but slow focuser, and ugly donut bokeh on out of focus highlights. Those tradeoffs don't matter when photographing objects miles away since you'll be focused at near-infinity the whole time.

Ah, the same ugly bokeh you get with one of the really cheap reflective mirror 500mm or 800mm lenses. I'd imagine all of these perform similarly or do you know?