[dadipentak]

I would think if a 100-300 + TC is under consideration it brings into play another option that hasn't been discussed; the DA*300mm + TC.

DA*300mm + Tamron 1.4x or AF 1.7x works for me.

[mikejustice]

Thanks to all, I decided to go with the Sigma 100 - 300 + TC option. I did consider the DA* 300 option but felt the versatility of having a zoom was important to me. I also want to let all of you know that as newbe your comments and advise not only helped me make my decision but also added to my understanding of what needed to be taken into consideration. I learned that there is no "perfect" choice, but rather it's a choice about what is best based on one's own needs and priorities. Thanks Again to all.

[Mike.P®]

Thanks to all, I decided to go with the Sigma 100 - 300 + TC option. I learned that there is no "perfect" choice, but rather it's a choice about what is best based on one's own needs and priorities.

A wise choice non the less .. (IMO).
Have you gone for the Sigma TC's or are you going to give the Tamron a bash first?

Look forward to seeing some pics with your new lens when you get it

[Lowell Goudge]

I would think if a 100-300 + TC is under consideration it brings into play another option that hasn't been discussed; the DA*300mm + TC.

the question is which TC, and also does the OP want a fixed ~500mm equivelent or something else?

That is why I like my 70-200F2.8 and the option of using either 1.4x or 2x TC.

If i don;t need the length, I shoot with the zoom only and have F2.8 from 70-200, If I don';t need all the length, I add the 1.4x and have 100-300 F4,

It gives a lot more options than the 50-500 or 150-500 with respect to speed at shorter focal lengths.

If he only wants 500mm then a 300 F2.8 and a TC is the way to go

[Oggy]

DA*300mm + Tamron 1.4x or AF 1.7x works for me.

---but not for me. I find I get better picture IQ with a crop from My DA*300 than I do full frame with it on the TC.

Also, the 300 on it's own will focus on an aircraft at 450kts in a 9g manoeuvre whereas on the TC it might focus on a stationary object in bright light.

[mikejustice]

To clarify, I have a DA* 50-135 which is my walk around lens, and whose optics I love. If I use it with the 1.4 TC I can only go to 189 at f4. With the 100-300 I'm effectively now covered the 135 - 300 range at f4 without using a TC. For longer shots, I will first give the tamy 1.4 TC a "bash" to see how it works. I'll probably spring for the 2X Sigma TC when my bank account is refurbished so I can then go as far as 600, and anything in between. We're heading to Florida for the holidays, and if I have any shots with either combination which meet the quality of what I've seen in the forum I'll post them when we get back.